seeing traxxas does not make a truggy at all kinda bad to ask about them in the truggy forum.
If you are planning on making a track the speed traxxas slaps on its over priced things is pointless as you will never see it. Remember that is top speed running it at short bursts at the point it could easily blow.
http://www3.towerhobbies.com/cgi-bin...&I=LXBWUW&P=ML look for that (prolly cheaper if you find it in your country) I own the older version and the older one is able to take a ton of abuse so I would expect more of the same from the update.
will it hit 50? maybe if you lean the engine out to the point it gets damaged.
Or if you aren't set on a truck look at the HoBao hyper 7 buggy (sold by HPI now) its quite a bit cheaper than anything you mentioned(and the truggy I said), and very strong, and will pretty much out preform the traxxas's for less