you dont need a 70mm a 65mm is fine unless prices are about the same then w/e..........everything works off each other so you should start with exhaust with a good mid pipe X or H i choose X, then intake not cheap Ebay stuff unless u get a good filter seperate or with it piping is the same, headers, throttle body, pullies, ( by this time your car better be tuned or its gona be running shi tty if you dont have cats plus the air fuel ratio may be off even with cats ) best thing to do is which is hard....by all the parts and install them all at once then get a tune ASAP....you'll see the huuuge difference and get a Mild Cam as well and high cam would not be meant for your car Naturally Aspirated...Im pushing more Rwhp and Trq at the wheels(196rwhp and 228rwtrq) with 3 engine bolt ons(mac intake,flowmaster duals,offroad xpipe) and a Sniper Tune then a stock V6 has at the crank which is about 190-193hp