It seems like after I've added some mods my car's performance isin't right.

Just recently I've added a Borla Catback, an SLP CAI and an airfoil. Before these modifications I ran 13.83 @99.28. 1.9 60ft goes with that one. I was happy with those numbers.

Now my car just dosen't seem like it's as fast as it was. A second time with the car at the track with the new mods got me to 14.1@98.0. 2.1 60ft goes with it. What I think that my problem is, is that maybe the car needs an LT4 KM because I run the Borla wide open. But then that makes me think differently. Perhaps I need to tune the backpressure and put a plate in there. If so which is the best with the stock manifolds?

I know this isin't right and I need some advice. Ask more questions and I will answer hopefully some LT1 buffs can help me!