I have this setup, specifically for the Chally I
http://csb-hype.5v.pl/?holzklau=A6B4B6C3C5C6D5D6E1E3F1F2F3
Retros:
Improved gun breech v2 - Rof +13%
Improved Pioneer toolkit v2 - Repair Speed +35%
Improved Filter Systems v2 - Acc. +15%, engine HP + 50%
Crew skills:
Driver: off road driving (+ acc), spin 2 win (+ hull traverse)
Gunner: do the twist (+ turret traverse), sharpshooter (-5% Max spread)
Loader: Explosive shells (+ module dam), vehicle expertise (+ repair speed)
Because:
The default Chally is painfully slow, so slow I want to rip my hair out, hence the speed/acc boosts,
Boosts to turret and hull rotation so they can't get behind you.
Since (in glops for example) no one can do anything to you from the front ... at all, they end up tracking you, every single time. You will be tracked, you use a repair kit, they will immediately track you again, and then you will spend half of every game sitting there, waiting for the repair timer.
So for this I have all the increased repair speed boosts/ increased track HP.