I run a duel pingle on my stock stroke ported banshee....IMO I like having the piece of mind. I may not 100% "need" it...but its worth it too me. They are kinda spendy though
I run the Boss radiator. $135 shipped to your door: http://cgi.ebay.com/ebaymotors/Boss-ATV-Racing-Banshee-YFZ350-oversize-radiator-/150556512102?pt=Motors_ATV_Parts_Accessories&hash=item230dde0f66#ht_500wt_956
I know you can cut your carb springs.... but make sure you cut exactly the same amount on each one. I'd only take a little off at a time to start with.
I've never done mine, but just heard of guys doing it.
Your going to get a hundreds of different opinions. Do a search on here, i'm sure you'll find tons of topics.
Me personally, I run CPI's on my banshee. Shearers are great as well.