If it's a stock TM:
-Don't run any more than the stock battery, 8.4v Ni-Cad/Ni-Mah, or 7.4v lipo.
-Don't upgrade the spring without swapping some other parts, namely the bushings, which are nylon in stock TM guns and can't take any more than an M90 or so.
-V3 mechbox is pretty solid but if you're planning on upgrading to shoot 380-ish you need to do quite a few other upgrades first.
If it's not a stock gun then the only way to confirm anything is to open it up and look.
"Someone in a Prius tried to race me at a stop sign the other day. I couldn't believe it. I had him for the first 100 feet or so but I can only walk so fast."