I just had my HPFP replaced 2 months ago and I am experiencing similar cold start symptoms again, slow cold start. Could this be ANOTHER HPFP failure or could it be something else like carbon? I really don't want to have to stock my car out to go to the dealer, last time I had it replaced I had an exhaust, but now I have a tune and bolt ons which may be an issue at the dealer.

 

Could be the HPFP or maybe carbon build up. I would have them look at the HPFP because it should be under warranty. If its fine I would check the intake carbon build up.