No need to spend that much really!
All the same principles apply to upgrading the S14, so the costing would be similar. The engine is easily OK with handling that, and the gearbox too. Maybe up to around 400 for the gearbox - I've heard they are not as strong as the auto, which handles around 450 comfortably.
So its maily turbo work, cool running, boost control, intake/exhaust, electronics.
But DON'T do anything on the cheap! It will be unreliable at best, catastrophic at worst! Expect a good few grand.
There are a few more extreme options, like fitting a Supra bottom end (2JZ-GTE) to create a 1.5JZ! Thats good for higher HP.
No Soarers have been used for drift in the UK, but there is one over here now that used to be drifted in Japan, and one of the VERY high profile drifters in Japan loves his Soarers!
They are heavy, but quite well-balanced.