Boxer12,
Yes, you can run 91 octane gas with the Mopar race controller, no problem....but.... if you get even slightly aggressive with 91 in the tank, the computer will retard the timing a bit which reduces power. No big deal on the street, but when you take the car back to the track and use 93 or 95 (some blend of 100 and 91 in my case), it will take a while for the computer to advance the timing again and restore the power you had before. Again, no big deal.
DP and Kenric,
Arrow Race Engines, who is the company that rebuilds our engines under warranty, put together a C & C ported lower intake manifold for our cars. They will ship you the ported "lower", you remove your OE manifold, take the top apart from the bottom, install the new bottom onto your exiting "top" (they provide a new metal gasket) and ship your OE lower back to them as a core.
On my car, it added power mostly at the top of the rpm range, from about 4500 rpm and up where our cam is working and our cars' power curve tends to flatten out a bit. Car pulls hard to redline now.
We ran back to back dynos on a Gen IV without it and mine with it. Same day in 98 F heat. RWHP gain was 25 with no loss of torque. No change in everyday drive-ability.
This is a very nice, inexpensive mod. I think I paid $550.00 or something like that. I did the install myself - it was simple. Call Arrow and talk with Todd: 248-852-5151.
If there is a downside, it's that you will hit the rev limiter easier now than before!
Dan