If im going for a manifold i would like a 2.5 instead of a 2.25 (i have an ek4), does a manifold for an ek9/dc2 sit much lower (5zigen to be prescise) than a 2.25 for an ek4?
It will sit a little lower not by a huge amount. It's the 4-1 design manifolds that sit the lowest so if going for a 5zigen 4-2-1 then it should be ok unless your car is really lowered and driving in a area where there is lots of speedbumps....