The LCR standard internals can take 320 ft-lbs and same BHP before they have been known to let go.
These have also been taken higher.
A OEM clutch can take the same figures if not given too much abuse.
Basically the whole system can take Big Turbo to these figures with out changing anything, apart from for fitting issues like Down pipes.
But to get the best out of any BT you will need a Front Mounted Intercooler, Freer flowing exhaust and DP, Cold air induction system or modified OEM airbox and air supply to it. DV needs to be changed as this could be the weak link to getting the best out of your system.
On standard turbo with the right mods you will get a fast well handling car for £4,000. For BT you will get a fast car for £5,000. On standard turbo with remap and handling mods you get a fast car with good handling for £2,000 or for a totally sorted very fast LCR with great handling your looking close to £10,000.
Hope this answers all your questions