did you leave the stock rubber spring bushings or go with polyurethane?
I love the quietness of this car and poly bushings work like a telegraph.
my car blows the doors off the comp stock in the qtr.
try some lucas fuel system cleaner. I run 1-2oz per 5 gallons and it helps with the throttle lag. I just go mine a couple of weeks ago and am not ready for a cai and I was amazed at the difference a drop-in k&n filter did. best $52.99 I ever spent felt like I got 8-10 hp and a lot more...