I had a PCMforless tune in my 08 3.7 and the improvement was significant over the entire power band. I think you are thinking of a CAI when you are talking about higher RPM's.
I did the PCMforless, Magnaflow Catback Exhaust, Airdoc CAI and an Alpha intake tube on my 08. I now have a stock 2010 Alpha and to tell the truth, there is not a lot of difference as far as drivability goes. Those mods made the 3.7 a little screamer.

 

I agree w/RKSmith. I have a Volant CAI, GM Performance Catback Exhaust, and PCM Tune from PCM for Less and it is a whole different ride. All together I paid under a $1000 for all those mods and they made a world of difference.

 

im betting gm could have done those mods at a factory cost of a couple hundred,offered them as the "ls" packgage for 500 and delivered a completly different veh,"the ls,,little screamer!

gotta wonder how they missed the boat and gave it to the aftermarket guys huh?

 

Well on that note "I wish you were the owner of Hummer drtom!" lol

(except that you might be out of business or not!)

Thanks for the summary of links Tainter! Great stuff!

 

Amen ! GM missed the boat big time with the Hummer.

I traded an 07 H3 with 18,500 Miles for the H3T in the sig... and would not have made the trade if the I5 ran better. While my H3T was being prepped by the dealer, they loaned me a 2008 H3 with a 3.7 and I couldn't believe how good it ran in comparison to my 07. As for the H3T Alpha, it also leaves easy horsepower on the table... I'll wait until it has a few more miles... then bump the timing... go to premium fuel... change exhaust and air intake... electronic fan... overdrive pulley... just a few tricks that will wake it up.

 

Well after all my procrastinating I went ahead today and placed my order with PCMforless..

Also as of a week later after installing the AIRDOC system I will be glad to let DOC OLDS know, the rough idle has gone away and she seems to be running a lot better. I think after disconnecting the battery and cleaning the MAF sensor has made a difference within the last 5-6 days..I really noticed a difference as of yesterday...

Now if I can decide to get the magnaflow exhaust or not lol..I'm just not for sure I want something loud although I want the performance out of it..

 

Would it surprise you to know your about an order of magnitude off. Aside from the plug cause I'm not sure if it's proprietary and has weird licensing the electronics are under 10 bucks for those programers and ODBII readers.