Don't get the Losi RTR, half the parts are discontinued and it's SAE.

Hobao parts you can get anything you want at hobao-usa.com. Ships out of TX.

Any race buggy will be 2x as more durable as their RTR counterpart, the RTR's all have cheapened metals, etc. Buying used is always questionable as the previous owner may not know WTF they were doing (especially with nitro). If YOU know what you're doing, it could be OK, but it's a lot better for an experienced hobbyist.