z3 kit uses a open dump wastegate or is perched on the rear stock manifold dp flange. You can't run a rear powerlog but you can run a front stainless powerlog and a rear PEM. Stock rear manifold directs cyl. #6 primary towards the downpipe, when really you want it going toward the turbo that sits on the crossover pipe. So you want the rear stock manifold ported a bit and the #6 primary cut and re-welded so its directing it towards the crossover.