Recently, our good friend, drove a very real and under-accepted point home; modifying your car does not increase its value. But, once we have finally accepted this very reasonable piece of advice, we're left in a no-man's land, frozen in the headlights, afraid to turn a screw for fear that we might as well set fire to a pile of money. Read more about customizing your car here.

The worst part is that, in almost every case, this proves true. Despite what many burgeoning enthusiasts think, adding very personal touches to your car will almost always drive the value down. And while there are rare occasions where modification will increase the selling price, this is the exception, not the rule. Of course, logic isn't usually a big part of Jalopnik culture, so let's examine how, when and why modifying your car might be a good idea.

First, let's talk about why. There are exactly two reasons to modify your car: financial efficiency and individuality. That's it. Individuality speaks for itself, so let's talk about financial efficiency. Essentially, the attitude here is, "I will build what I can't afford." If we could afford to buy a Ferrari, we wouldn't bother bolting a supercharger onto a Corvette.

Of course, no matter why you do it, you're still risking devaluing your car with every inch you move it away from stock. With that being said, here are the acceptable scenarios for modifying your car:

1. You don't care about money. Let's face it; logic isn't the strong suit of car culture. We're prone to irrational car purchases and even less rational modification ideas. Many of us have taken on wildly risky project cars after convincing ourselves (and usually our significant others) that the cost of a project would be reasonable. As it turns out, "reasonable" is a pretty big gray area.

2. You're not going to sell your car. Since I started driving, I've owned 12 cars. I have only sold one of them for a profit. The rest were either passed on to a family member or met their untimely end on the road. The point is that I just don't plan on selling any cars that I own. My goal is to drive them into the ground. I seem to have inherited this from my father, whose 1970 Volkswagen Beetle has a little over 700,000 miles on it.

If you never plan on offering your car up to the market, you'll never have to explain the choices you've made. The choice to buy those $1400 wheels is between you and your God.

3. Your car was a lost cause to begin with. Originality will almost always trump modification in the marketplace, but there's an exception if originality was never an option. When I bought my 1967 BMW 1600, it was basically a rolling shell. There was no interior, the dash was in pieces in the trunk, the original motor was on it's way out, and the outdated suspension was begging for death. So, there was really no where to go but up. I think that it's a safe assumption that the car is worth more with the E30 4 cylinder and upgraded the suspension, wiring, and brakes than it was when it limped off the trailer.

Now for the how. Here are some basic rules for modifying your car that will hopefully allow you to satisfy both your desire to modify and your desire not to make your car worthless.

Purchase a higher flowing exhaust. If the intake is how an athlete (your car) breathes in as it runs, the exhaust is how it breathes back out. There are a number of options available to you when it comes to installing higher flowing exhausts. Many people opt to install a catalyst-back aftermarket exhaust, which replaces the piping from your catalytic converter(s) to the muffler. Higher flowing catalytic converters, front pipes and even exhaust manifolds are all also common modifications. Replacing the entire exhaust system (from exhaust manifold to muffler) will maximize the performance of your engine.

  • Larger diameter, higher flowing exhaust systems have a more significant effect on turbocharged vehicles. The increased exhaust flow also serves to increase the efficiency of the turbocharger.
  • Some states have strict regulations about replacing your catalytic converters. Check on the website of your local Department of Motor Vehicles prior to modifying or replacing your catalytic converter.

- Consult Professionals. If you're looking to upgrade something, do it right. Ask the old guys on your car-specific forum. See what the tried and true upgrades are. Don't take your car to a shop that has never seen your model; seek out the knowledge of the elders.

Give Your Ride a Nose Job The age-old practice of removing factory insignias and nomenclature has come to be known as “nosing” in the hotrod community (not the same as ricers). Technically it’s not free, but for the low-low price of adhesive remover, dental floss and the power to run your hairdryer, you can transform your daily driver into a custom one-off. Factory insignias and nomenclature don’t look like much at first glance, but you will be shocked at how much different your car looks once they’re removed. If you're the lucky owner of a car that doesn’t use glued-on insignias, you’ll need to devise a way to fill in a few mounting holes. Either way, there’s no shortage of handy guides available.

- Keep the original parts. If you "upgrade" your new Camaro with low profile tires over bigger wheels and new suspension, do yourself a favor and keep the original stuff in a box in your attic. When it comes time to sell the car, you can return it to stock. Then just unload the enthusiast parts to other enthusiasts. Original parts may seem worthless now, but they will be rare and irreplaceable at some point, so you might as well keep them.

- Don't make irreversible modifications. Don't cut holes that you don't need to cut. Try to limit yourself to bolt-on modifications. Don't cut the wiring. No one wants to deal with your mess, so take your time and make sure that you can return your car to stock as much as possible.

You need to abandon your dreams of 300-lb subwoofers and back-seat hot tubs, but not all is lost! You can still give your car a little something special to make it stand out from the crowd. Customizing your car doesn’t have to break the bank. Done right, any one of these affordable modifications is highly likely to fool your friends into thinking you employed the services of a professional auto-salon. And nearly every one of these can be done at home with just a few simple tools.

- Go with the flow. No matter what you are modifying, a car company likely invested a lot of money into its development. It's unlikely that you are not going to eventually regret major aesthetic modification. So, try to understand what the manufacturer was going for and improve ever so slightly upon that idea. If your car is a base model and an upgraded version exists, look to that for inspiration.

- Don't expect to make money on a modification. This is probably the most important piece of advice that I can give you. Figure out exactly why you want to modify your car and act accordingly, but don't tell yourself the lie that you're making a good investment. Sure, it's possible that a new set of upgraded Bilstein coilovers are going to increase the price of your BMW, but it won't be comparable to what you actually paid for them. If you want to modify your car, go ahead, but don't delude yourself with dreams of raking in the profit because you bought some parts on eBay.

Of course, all of this is just opinion that I've developed in a few decades of car ownership, maintenance and modification. I'm not professional, but then, neither are you, right?

Customers’ ideas can get pretty wild.

The luxury brand notes that “no request is left unexplored.” Its team of designers has matched leather colors to customer lipstick, sourced wood from a tree on a buyer’s estate, and found ways to pack elaborate picnic sets and wine glasses into their cars.

From the unexpected demands of wealthy buyers to the special edition cars it makes to mark special occasions, here are some of the most outrageous ways you can have your car made just for you.