The only aftermarket arms Ive found are aluminum which I would stay away from because they bend. If you are using it strictly on road than it might be ok. Unfortunately RPM doesnt make arms for the MT2. Ive emailed them a few times but there doesnt seem to be enough demand for them to make them.
Ive run mine on an indoor track a few times now and the only real problem I noticed was that the stock tires dont hook up well on hard packed surfaces. When youre bashing it doesnt matter but when you are trying to make a hair pin turn on a tight track you notice. Pin type tires would work better on hard tight tracks. But other then that I hung pretty well with the brushless buggies that were running on the track at the same time.