Just to add to the above, the standard Toyota clutch is more than capable of handling 300bhp unless you are planning on regular visits to the drag strip or indulge in the traffic light grand prix starts on a regular basis
I ran my 330bhp ST205 for several years on a standard clutch with no issues until I tried towing a fir tree out of the back garden (don't ask!).
By the way, looking at the TCB site they don't list the Aisin clutch for the ST205 but they do have the OEM Toyota organic friction plate. An organic clutch is a lot more pleasant to use than a ceramic, puck or paddle type clutch which are much more 'digital' in operation and can thus be a pain to use in stop start traffic.
P.S. Another vote for Martin as a good GT-Four expert in your area