Hello, and welcome to the boards.
1.It will take awhile for you to notice the expansion chamber starting to freeze unless you are on full auto. In semi, playing in decent temperatures (45 degrees and up I'd say) you'll never have a problem with it freezing unless you're on full auto for several minutes. But playing in the winter, you might notice it begin to sweat, but I doubt you'll have a problem during play with it freezing up as long as you're in semi.
2.Spyders and their internals are capable of cycling 55cps (cycles per second) as far as I know. This means with an upgraded board, upgraded reg/HPA system that recharges that fast, and a hopper that will keep up, you could achieve very high rates of fire. I think the fastest I have seen is 48cps so far, but no loader can keep up with that so if you bought a T-Board and a Halo B you could up your rate of fire considerably.
Hope that helps you a bit.