Here's my dilemma - Currently turning standard mirage (not plus) 25's @ 4500 RPM (twin 330's 32 Sunsation) 66 GPS Looking to eek out another 1 or poss. 2 mph - If I ran a set of 23's would this give me more speed or just increase my RPM?? any suggestion's - what's the differences between mirage plus & the regular mirages???

I'd say get the ones you have labbed.

You will spin about 200 rpms slower if you go to a 25 Mirage+ about 200rpms faster with a 23 Mirage+.

Your 330's should be operating between 4200-4600(I think). Preferably towards the upper end of the range. I'd stay with the 25's and get them labbed.

The 23's would be a great holeshot prop, but would be innefficient in cruise and probably hit the limiters at WOT.

I have a very nice 25 Mirage that you might want to have labbed, that way if you don't like it you can go back. If you do like it sell the 25 Mirage. The Mirage is real cheap if you want it.