1. dont think the magpul is in production anymore? which even if you get one 2nd hand is a bad thing. I do love bullpups, but the AUG trigger is pants to the degree that I don't want to use the gun.
2. I'd go for electric. gives your a plan B if you miss and could be used as an emergency assault weapon if enemy isn't too close. thou that technically be a DMR not a Sniper. if you want a bolt action, then spring.
tl;dr:
1. Neither.
2. a ) DMR - electric.
2. b ) Bolt action - spring.