I got a hold of this brand new, really old stock G15. Has a throttle and the coupled exhaust baffle with no muffler like they were. Could have saved it for posterity or made some $, but it is only money, you can always get more of that. Very loud. My usual test with a Master Airscrew 7-5" G3 prop and 10% nitro. It only has about 2 oz. through it now and seems like just over 15,000 rpm is going to be it. It does not feel tight or anything. I did not think it would be slower than the LA and even the much older OS. Maybe the big red control line venturi is bigger and it will pick up a bit.