Okay, whoever said the Impulse is not accurate at long ranges, we need to meet some time. At the break, just stand there on the opposite side of the field for a second or two. I'll let ya get a first-hand look at a rail of paint from my Impulse/Freak combo. We can talk about it afterwards, okay?
(I mean, I'm sure you know that the accuracy issue is mostly controlled by the paint/barrel match)
So far as being a back player...
1) Do you already have a good gun? Always have a back-up! The Matrix is new to the market and there is a slight chance that the one you buy will have a few problems early on. It would SUCK to call it a day (especially if it's at a tournament) because your one and only gun goes down for the count. Understand this, though... I DO support and think very highly of the Matrix, okay?
2) Get the biggest tank you are are comfortable handling. If you go with a Matrix, consider a 114/4500 (or maybe a scuba tank and a back-back! LOL) Yeah, that's a pretty hefty tank, but if you're normally staying in the back playing Eagle, it's not nearly the issue it would be for the middle and front players.
3) Possibly consider going with CO2: One of my teammates is a Shocker nut, and he uses a pretty hefty CO2 rig w/ an anti-siphon because it gives him a lot more shots than a nitro tank of the same size. CO2 does not equate to 2nd Class citizen (I suppose.... LOL, sorry Jeff)
4) I'm not sold on the Intimidator yet, dude. Another one of my teammates owns one and he's not only had a few recurring problems (like most any new gun to the marker will have) but his was chopping like crazy last time we talked about it. So far as the Impulse is concerned... I know people (one in particular who is very knowledgable, mature and has quite a few years experience in this sport) who use their Impulse in big tournaments (ie: Marti Gras, etc.)
Okay, enough babbling from me already!!!
Good luck, man!