I've been considering buying a performance chip for my 4 banger, but have read some mixed reviews. Some people claim 10-15 hp gain, others say they are garbage. I've seen them by Jet and Venom. Anyone have one installed and do they actually work?

 

I have a Jet stage 2 on my 4.0. Yes you can tell the power increase but on a 4 banger I'm not too sure..Are they worth it, if I could go back I would have got the Hypertech one that has more options but too late now...