[slim_n54]

Little worried. Installed Cobb Accessport a few weeks ago running stage 1 aggressive. 2010 N54 335i. DCI and M Performance exhaust. Was driving the last few days and at about 3/4 throttle the car starts to sputter like it's holding back. Uninstalled the tune, no sputtering even at full throttle. Figured it was the plugs and that I need new ones, colder NGK plugs. Before I replace those, is that what the issue most likely is? Or is it more likely to be a HPFP or even the coil packs?

Any ideas?

Thanks guys.