I have been giving the AMS and Buschur intercoolers they eye ball for the last few days. AMS clames that the intercooler alone is worth 20hp and it doesn't come with the lower piping but I already have it and it tested out at 5-7hp improvement. I am sure Buschur's intercooler would yeild the same results but is this true that just upgrading the intercooler alone would add 20+hp? If so why wouldn't other people do it even if the stock IC is good for 400whp.

 

do a search on this.. there's plenty threads explaining why they add hp..

 

As far as why everybody doesn't upgrade the I/C... Bigger intercoolers improve HP, but they generally also increase turbo lag by increasing the volume of air between the turbo and the intake valves. More volume means it takes longer to build up pressure.