I'm running a straight pipe 5" exhaust and am putting a no limit piping kit on Thursday. Hopefully that helps a little with lag.
Have you tried driving it in towhaul? It holds gear longer and downshifts quicker.. that is what i have done in my 12 and now in my 15 with stock turbos to keep it virtually smoke free. Worth a shot anyway.I'm having similar issues. I'm running a 364.5sxe MPD budget kit with tyrant tunes for a non vgt turbo and its very laggy and smokes constantly when in a high gear and slowly accelerating. Curious if I'm just going to have to get used to driving with the new turbo or if tuning could help clean it up.