Body Kits installation should not be taken lightly. It's important that the kit you add not only look perfect on your car, but allow your car to function impeccably. Well, there are a few things that you can do to help your car fit perfectly into its new skin. If you're going to drop all that money on the parts, you may as well make sure that you're putting them onto something worthy. That means complete perfection, starting where it counts: on the inside.
Get a tune up and an oil change, check your fluids, test your battery, spark plugs, tire treads and make sure all of your lights work. The little incidentals are what really make or break other people's impressions of you and your car. A rattle in your engine or a squeak in your breaks will completely downplay any extras on the outside. If it looks lovely, but sounds crappy, no one will want to get in. Also, knowing that everything under the hood is solid will just make you feel more confident about showing it off.
The next step is to pound out any chinks, literally. Adding body kits to your car will really stretch out the lines, make it look classier, and sportier. If there's a big dent in the middle of your door, though, the body kit can't do thing to help you. People will wonder why you bothered to spend money on the spoiler, but not the original car. This also goes for any cracked windows, broken mirrors, or smashed tail lights. People's eyes should go to the extras and not the "uh oh's."
The very last thing to do is get a complete wash, wax, and detail. This does a couple of things. First of all, it makes your car look shiny and new, just like body kits will. It would be silly if the colors didn't match just because you were too cheap to wash your car. Secondly, you know you're going to want all kinds of people to come for rides, so you don't want the inside to look anything but brand spanking new.
All these things seem silly, and perhaps like they really needn't be bothered with if there's no big problem, but it all gets at the very heart of purchasing body kits. You want your car to look good so that you will too. You're showcasing your taste and your ability to maintain something beautiful. Your car really can't be a mess when it's about to get a fresh body kit. There's no point in spending hundreds of dollars just to end up looking silly when you need a jump on the way home.