I went with the 300hp kit. I would get a chip along with the jmod. When I did my jmod it would shift way to early around 5,000rpms. It wouldn't even chirp 2nd gear. With the chip which was a diablo chip burned for a stock 94sc auto it would chirp 2nd and 3rd at full throttle. Dunno if my it was the way my tranny guy did it but I have read on tccoa that some people have experienced similiar problems with the jmod. BTW my diablo chip is up for sale!!!