My impression is this: the stock "midpipe" is the most constrictive in the exhaust system. To change the "cat-back" system will result in a change of tone, and you will also see a slight increase in torque and h.p., but to change the pair is the best option. Another impression I have is that the reason there is so much time and emphasis on "cat-back" systems is becuse most states test for emissions output. I am from MI, and we don't test for emissions, so I am currently working with a co. to develop a number of fuel, boost, and intercooler systems. I am offering up my own RX for testing/development, therefore I am putting my "money where my mouth is". When my/our various systems reach full development we tuners will see performance potentials that rival that which we read about in magazines but will also be fully economical and streetable. If you wish to ask questions, contact Charles R. Hill (me) and we shall discuss said developments as much as legally possible.
Thanks for being there,
Do NOT send me a PM here. E-mail me at "Charles@BlackHaloRacing.com".