Put whatever you like in it. Don't think everyone else has to approve your modifications. I put a 5.5t in my boomerang and it lasted fine. Yet in a tt01 it'll rip it to bits in seconds. It's all about fine throttle not just stabbing the power on. A hot motor in a hornet would be a right laugh. Maybe not the most long running but sure fun while it is. Tamiya aren't the best plastics in the older cars. The arms tender to snap on hotshot or boomerang so that got boring quick. Not gearboxes or spurs like a lot of modern cars. I've got a 12t brushless grasshopper which runs on a 3s. Yeah it kills tyres bit so does my mates dex210 cos he's so hard on it.