Do you have headers? If not then you should consider their
stage I instead. There isn't a significant difference other than
some a/f nudging due to headers.
Powerchip concedes that the only benefit from their software
is 8400rpm, delimit, and throttle response. I believe they are
the only company that doesn't claim any significant hp/tq gains.
This is not to say that their software is inferior in any way,
rather I think they are more realistic/honest about things.
Recently there's been a lot of buzz about ESS. Almost everyone
that has their software installed loves it (one notable exception
which is being worked out). They have posted dyno gains and
sounds like there will be a few videos up shortly to show a
stock vs. ESS tuned car.
I have Powerchip stage II right now but I've also purchased ESS.
Yes, it sounds retarded to have both but I have my reasons.
My personal opinion is to go either Powerchip or ESS. Dinan
sounds decent but you're kinda stuck with Dinan stuff aftewards.
ESS and Powerchip will custom tune based on your setup.
I'll be doing some "extensive" testing of Powerchip vs ESS software
this summer (End of May). If you are considering either one of
these then I would suggest waiting until I can report back.