I would spend that money on a full exhaust system including a sports CAT. They are better to use than de-cat pipes because it does allow better air flow but also retains the legal limit for fuel emissions. go to:
http://www.milltek.co.uk/catalyst.html
they do sports cats and full systems. Not sure about he price though. If you can't get one in that price range then you can get the de-cat pipe if you want to risk the failing of the MOT.
Definately get a full system though, any brand name should be a quality product, such as scorpion or milltek(also do a dual exit system).
As you have an induction kit i would spend the rest pof the money on set of kent cams or piper cams. This should see you at about 115-120bhp on a MK2 VTR, 100bhp standard or 105-110bhp on a mk1 vtr, 90 bhp as standard.
Also when fnuds allow your next mod to tie it all together be a chip. You'll then see 130bhp/120bhp or so i would think.
Im going for the VTS conversion in a couple of months hopefully as funds allow. Its upto you really, if you have a MK1 VTR then i definately would or if you have done many mods yet then it may be cheaper to sell the car and buy a VTS. When tuning the vts you will see even better power gains than on the vtr. let me no what you do