Thanks for the quick responses folks!

I will email them my pipe dimensions and see what they think re: performance/fuel on the current pipe.  It is not the stock one - I had Tam make it longer and to suit the Rabbit better.

P80SE does not have much more power, uses more fuel and is much heavier than the Rabbit so it's not a great solution IMO.  P120 would be overkill and I imagine it would drink 84oz very rapidly!

I'm going to improve my intake ducting - but at the end of the day I still need more power to fly it the way I'd like to.