I've driven both cars, seen both installed, and helped with the GrouppeM SC install. In all fairness, the Grouppe M was probably not installed right, so I won't comment on the GrouppeM performance much (I think there was a boost leak).
I believe the Comptech is a much cleaner installation, and fits better in the NSX compartment. It does not hamper rearward visibility like the GrouppeM and is more inconspicuous. I believe the Comptech unit is easier to get replacement parts (USA vs. Japan).
The instructions for the GrouppeM are good (they were translated from Japanese) but I believe the Comptech instructions are better.
The GrouppeM has more HP potential than the Comptech in theory, although I do not believe this has been proven beyond Alex's dyno'ing his car against CT SC NSX.
Alex (who is the GrouppeM distributer in the US) has done a fantastic job bringing these products to NSX owners in the US.
His car is fantastic, a museum on wheels.
In summary, I believe the Comptech unit is more refined, and possibly has better support, however, I also believe that the GrouppeM unit is a very capable system that has the potential to beat the CT system on both HP and torque numbers.
This is all IMO of course. This thread has been hashed upon on the NSX list frequently.
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Chris Willson
www.ScienceofSpeed.com
www.NSXClassifieds.com
[This message has been edited by ScienceofSpeed (edited 30 January 2001).]
