ok well i have had my 07 Z about 3 months. added k&n drop in's , stereo system, and today put turbo xs test pipes on and installed cobb stage 2+.. i know alot of peeps say uprev is way better but i got a good deal on a cobb.. and i have to admit after installing the pipes i drove it abit, i could tell a slight diffrence , but when i added the cobb stage 2+ it really brought it to life, i have read alot of peeps getting hesitation around 3k rpm, in my case there was no hesitation but the pipes do resonate abit louder around that rpm or rasp, but it does not bother me..i have not enjoyed a vehicle this much since i was 18 with a brand new 93 mustang gt.. Thanks everyone for all your time and input here on the forums, it has really helped me alot in figuring out what helps and what will not..