stock rb30 bottom end from a series 2 VL non turbo.. there are a couple of people making good power.
guy on here used a series 2 VL rb30 bottom end (with over 300,000kms on it) stuck a stock RB25 head with upgraded valve springs, GT3540 turbo, external wastegate, 16 psi boost and made 306rwkw.
that's one good example.
SK has built a few in his time.
one of his has now got over 70,000kms making 450hp.
RB30 bottom end can be had for about $100.
put in new rings and genuine bearings, your current oil pump, new water pump, new tensioners and new timing belt.
you current head will bolt on to it with no problems.
you will need to work out a way to get oil to the head for the VVT to work.
there is a great DIY guide put together by user on here CUBES.
there is a link to it in his signature file.
yes it will be heaps more streetable at 300rwkw compared to the rb25 at same power.
Brakes - cheapest way to get more braking power would be some DBA slotted cross drilled discs, new Feroddo brake pads, Motul dot 5 or higher if available brake fluid, and a brake master brace.
or you can go all out and get some big brembo's and suitable discs.
LSD and suspension will all help with traction.
do a search in the appropriate section on sau.. there is a braking and suspension section .