go on ebay and type in tamiya tt-01 or check out the variants, they are great fun but will cost about £80 used with controller etc. in shops they cost about £150 new.
these will go about 20 mph on a battery. very good fun.
Check out www.modelsportuk.com these arethe best around in my opinion. Got my Savage X from them and they are really good. Not the cheapest around but do have some good deals on now and again. If you want speed you need a nitro car as these tend to be a quite a bit quicker than electric.
dude go for 2nd hand nitro car/buggies/monster trucks!!!!
way better than electric.
i've got 3 sat in my garage now two nitro and one beastly petrol buggie.
although electric is more reliable nitro/petrol are alot fast and sound ace two.
so if i were you i'd forget electric and move onto petrol/nitro.
of ebay you can get some nitro buggies for less than 100 like the hpi rush evo.