lol suspension modifications dont stop at buying some coilovers. pineapples, caster, camber bushes and swaybars still to go.
Do some reading here; http://www.skylinesaustralia.com/forums/Rb...no-t103095.html
I think you also need to think about what exactly you are after. Why did you mention 300hp for? If you are interested in 1/4 times, then you should first choose a time you are after and then work out how much power you would need to have to gain that. 1/4 mile comes down to driver skill in the end. If all you do is wheel spin and/or bog down from the line, you will always get a shit time.