someone is selling power FCs on ebay for the FC3S. are these good systems, or would i be better off with the haltech. i see more people using the haltech, but im not sure if its due to availability or quality. http://cgi.ebay.com/ebaymotors/ws/eBayISAP...item=2457698371

The PowerFC is good, but it uses the stock wiring and sensors. These are 15 yr old cars, the wiring a lot of times isn't in the best shape. I'd rather use a Haltech mainly because you get to use new wiring.

Awesome, but like he said, you get a new harness with another ecu. The beauty about the system is that you can easily go back to stock for emmision or smog. If i had an s5 i wanted to slightly mod i would get powerfc so I can stay, well sorta legal. Specially here in cali.