I don't like most custom ones since most people aren't as good designers as the original car designers themselves, and therefore cannot compare. Although, I'll admit, that the EVO in generally looks like ass mostly.
There are 2 types of stock Lancer spoilers. The OZ Rally's is small, with 3 pillars. The EVO's is a higher wing. I like both, but the higher one looks more like a racing car, and I like that.
Well, the only time I've seen custom-made spoilers is when the person has modded their car to hell (complete body kit, tire switch, rims, headlights, the whole deal). It wouldn't look right putting a custom spoiler on a regular car, in my mind. But I don't live in Cali and don't see weird things with cars daily. The EVO isn't that pretty a car, heh. I'd agree with you about that.
I haven't seen the OZ Rally's one I don't think, but I've seen the EVO's one and it's a pretty nice compliment to the car.