With about a grand u should be able to push 60-80hp...most topend pipes will bring a stock motor to about 40-50hp and thats inframe(to be more specific pipes like CPI,T5,T6, ect... U could get pipes and a 4mm stroker kit u could prolly pull 60-75hp maybe even 80hp but 6 thousand u can make a 120hp shee like said above..First thing i would do is make the shee lighter and maybe wider then get some good shocks like elka triplerate with rezzies (fully adjustable) But there have been a couple of ppl on the HQ who have put the YFZ450 front shocks on a banshee and really like the change. New suspension makes a big difference u might even notice u go a lil faster....I would say buy a play in the yard banshee and a play in the sand/drag banshee......But when u have about 80-100hp it's kinda hard to keep the front end on the ground. I recomend u gradually make ur shee faster becuase if u throw everything in at once u will either be scared of it or once u get used to it u will not be impressed. Take ur time u might need the money for somthing else that is very important............Back to the modz i like rdz they have pretty sweet parts but a couple ppl here dont recomend them,i havent even contacted or bought anything from them so i have no expeirience for $550-600 with shipping u got urself 90+hp try throwing $600 into a 30hp 4 stroke and tell me what u get <_<Thats why all these new atvs suck..damn 4 strokes,but i will have a 450r soon so i should just shut up also a stage four port job is 105hp Level 4 port Then throw in a stroker kit12mm $1500-2000,K&N filter, and an override trannytranny That should be fast enough I dont recomend RDZ cuz some ppl didnt recomend them to me so dont go buying stuff right away.
Im kinda tired i gotta sleep it's 12:40AM!!