I just upgraded my machine with the following:
ARH longtube headers, high flow cats and cat-back exhaust
"Track Cam" from Synergy Motorsports (New design, not yet on website. Call them to order it)
Rockers, pushrods, double springs, Etc.
Dyno tune by Synergy
The results were surprisingly good, considering I asked for a cam that was optimized for the beating that engines must endure on road courses. So Rick at Synergy designed a relatively mild cam that won't abuse the valve springs. The lift is high but is less than a typical drag cam, so that if god forbid I miss a shift, my pistons won't become intimately acquainted with my valves
I'm very happy with the results: 478 RWHP, 445 Ft-Lbs to the rear wheels!
The idle is slightly lumpy, just enough so that there is no question that this bad machine is cammed. It sounds the way a muscle car should. And the complete ARH exhaust system has a nice deep sound. Not as loud as my friend's Borla Atak, but it roars when you get on it. Nearly drone free. Maybe just a touch of drone when cruising at around 1500 RPM, but that's in bog territory and I don't often go there, LOL. Very smooth and well mannered on the street, no bucking or other issues.
I also decided to make it look good under the hood. I've had fast cars before, but the engine bays were always fugly. So this time I went with some Roto-fab engine covers, carbon look intake cover, and and carbon look CAI. Some pieces are painted to match the factory Inferno Orange Metallic paint. Maybe they're not go-fast goodies, but hey you only live once.
UPDATE: I tracked the car at Buttonwillow, and my top speed on the road course went from 113 MPH to 130 MPH. The changes were the engine mods plus new R-compound 315's. I've added a video of the exhaust note below. Click the last link in my signature to see what it sounds like from inside the car, at Buttonwillow :big grin: