So I bought a B44.1 about 6 months ago or so after spending about 13 years away from the hobby. I always liked 4x4 buggies, but as a kid they were always a bit pricey. My plan too was to bash mostly, race maybe.

Here are my thoughts, then I'll answer your questions.

It isn't the toughest vehicle at all. I have broke 1 front a arm only though. My shock towers are a little scratched at the top, however that is mostly from a clay racetrack. Just be careful I guess =] There are aluminum parts I haven't used yet, but would explore for bashing. I use Proline Dirthawgs for road driving. You can easily traction roll on concrete, especially at brushless speeds.

I would highly recommend the Tekin RS Pro. The small footprint is great for a cramped chassis and no motor limit is a plus.

I would go for a 10.5 motor. I have an 8.5 currently. On the racetrack, my skills have me nowhere able to top it out at all. When bashing, power is addicting and you always want more. A 13.5 may leave you a bit unsatisfied. The good news is there are many ways to dial speed out, although learning throttle control is a big part of racing. The Tekin hotwire will also give you current limit settings to dial some speed out. A lot of fast racers will likely use 6.5 - 8.5 turn motors, so 13.5 is definitely a little slow in that sense, although your car will only go as fast as you can drive it. I again, have not personally been able to fully use the 8.5 turn power on my local track.