I'm experiencing bumpsteer while taking turns at speed. The steering wheel kinda pops out in another direction if I hit a bump through the turn. I heard a rear bumpsteer kit is not needed for an AP2, so will a front kit alleviate this?

Alignment has been done and is within specs. I'm driving an 04 lowered about 1.5" on GC coilovers w/ oem shocks.

 

Dunno the answer. But just FYI I am lowered same amount and my cat doesn't do that. You might have other issues. I also have a highly modified AE86 as well. And that car does what you observe very heavily. But through many forum suggestions and discussions, I have come to the conclusion that what I thought was bumpsteer was just steering input from the fully-metallic suspension (no bushings at all.) But that's probably not your situation, as I doubt you went that far with the mods. So, again, my car is lowered almost as much (HKS coilovers, but shouldn't matter), and there is no significant steering wheel tugging at all going over bumps.

 

Just to clarify, Bump Steer can only occur at the front of autos (unless they have 4 wheel steering); Roll Steer occurs at the rear. My perspective is it's easy to check for either; why not set them up and run the numbers. However, 37,5mm lowering would definitely get you near the neighbourhood of these maladies.

May I further suggest that you may be hitting the bumpstops which effectively sends your rates to infinity. This will cause all manner of havoc with the handling making it difficult to diagnose