I have run the Axial .28 1s in my back up buggy and have nothing but good things to say. It all depends on the track you race. If you run 15min mains everyone has to pit so the mileage problem won't hurt as bad. I get about 8 minutes from mine and I don't run a carb restrictor.

I have also owned a Hyper .21 8 port (older model) and I can say is Axial will perform better. The Sportwerks .26 engine has more top end and can be had for a little more than $100.00
Never owned one but I can tell you they make great power for a budget mill.

You may want to consider this Nova Rossi engine as well. You would have to ask around as I have not owned this particular model but there race engines are top notch.

http://www.amainhobbies.com/product_...ducts_id/31073