Running a DMR much like a Bolt Action isn't cheap. I love mine but it was a £325 gun (which has since gone up in price), that I sent to Negative Airsoft and paid him about another £300 to make it top notch. Heavyweight BB prices will make your eyes water too. Sure it's fun to justify a scope but I still get hit as much as I would running a regular rifle.
Who actually uses a pistol full-auto? (I mean apart from Novritsch). At the only distance I've ever tried to get some serious use out of mine, it'd be frowned upon and possibly even against the rules to shoot full-auto. Plus you need to consider mag capacity, cooldown issues (especially on metal slide guns) and the fact that accuracy tends to go to crap too.
Despite the plastic, TM's don't break easier than others. In fact it's far more common to find bits missing or not working on other brands. Their QC is second to none.
I'm not trying to put you off, just manage your expectations.