There was a guy in one of the car mags driving a modded up Hyundai Accent. The article said it was like the second or third fastest four cylinder car in Australia... THAT'S repectable, even if the car is barely running any stock parts at all.
When it comes down to it tho, get what you want for your car if you think it looks cool. Today this red pulsar came past me, lowered, custom paint job, custom body kit and bonnet, bigger exhaust, the full timers and stuff on the bonnet, bigger wheels, and I just looked and laughed cause i could picture my grandma behind the wheel of a pulsar, but obviously the owner thought it was cool, and in the end that's all that really counts. So go for it mate, if you think it looks cool then do it. Don't worry about other people.