every1 says they do?????

 

It really depends on what you are looking for. I have one from Phearable.net and it's great, fuel maps are adjusted a little to account for I/H/E and my car runs much smoother.

Most ecu's you buy off ebay have chips in them that say mugen or some other program used which all they do is advance the timing and put way too much fuel in the chamber possibly causing problems.

 

every motor is different, and has different needs. when you go and buy a generic chip, like those found on ebay, the chip doesn't match your motors needs. if you get a chip, it should be adjustable/tunable, and you should have it tuned when installed. a generic chip it like putting a H23 ECU in on a H22, the setting just aren't matched up to your motors needs.