Daves Surplus in New West is awesome. There's also Gorilla Surplus on East Broadway in Vancouver. Whichever is closer to you although I prefer Daves because I find they have a better/wider selection. With Gorilla it has more of a "surplus/antique" feel to it (a place where collectors would shop IMO) whereas Daves, although they do sell surplus they have a more "tactical/surplus" feel to it a place where currently serving LEO and CF kind of people would shop. I don't know what it is, maybe the ambiance or something but that's just what I've felt. Neither is better or worse in terms of customer service, they both helped me out a lot and were always ready to answer questions.
Most guns in the classifieds are upgraded, some stock (maybe 70% upgraded, 30% stock). The degree's to which they're upgraded might be different, eg. to the nines with 400 FPS, reinforced gearbox, good hopup unit/rubber, tightbore etc. or it could be as simple as a few parts that broke and were replaced.
Personally I use my hiking boots but I recently found out that "combat boots" allow you to run more freely with the same amount of support. If you have hiking boots they should be fine. For reference I got mine at Coast Mountain Sports IIRC (although it could have been that "outdoors district" on Broadway though (MEC, Altus, Europe bound, Valhalla Ice, etc.). When you do purchase make sure it has good support all around, it should have a steel shank running from the heel to about 3/4 of the way to your toe, slightly less that where the balls of your feet are, and a composite toe. Doesn't need to be CSA approved but if it is then you can wear them on worksites and whatnot.
I wear a cotton t-shirt sometimes and other times I use my polypro from MEC. Depends on the weather that day, if it's going to be hot then cotton to cool you off, if it's mild then polypro to wick away your sweat and keep your body temp regulated.
If you're running a crane stock I'd go for a PEQ/LAM to store your battery wired to the front. That way you can use a large battery and should be able to run on one battery for the whole day.
Hope that helps.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE