Plane jim sorry didn't get back to you the site wasn't notifying me when people respond and haven't been to this post for a while... I'd have to measure the prop... I got it on trade for an e-max I had... But I think when I got it it had a 10 / 6 wood prop and I switched it to a 10/ 8 APC I know it definetly went faster with the apc on it. It's a Thundertiger pro 61 with a pitts style muff. As far as the wheel bracket being backwards could be I'll have to take a closer look. The guy I got it from said the wheel area broke off and he fixed it.. I peaked inside and its reenforced. The slanted side when I just went downstairs was to the back side... BUt the wheels are at the front edge of the wings... Will have to check it out. As far as 4 stroke vs 2 stroke... If you want torqe to pull you straight up and do acrobatic style flying or after four feet straight up the 4 stroke will throw a bigger prop and do the job... but the top end of the power band is lower.... If you want speed go with the biggest 2 sroke you can put on it and the rpms are higher... Takes longer to get to the top end but it will SCREeeeeemmmm!!!