i was thinking about it but it's not worth the effort in my opinion. Your going to need the 6 speed tranny, new clutch, flywheel, driveshaft, rear diff(preferably axles and brakes since your already this far into it), a wiring harness and switch if you want to use the DCCD, an ST-i shift linkage and shift knob and some tranny mounts. I stripped out first gear in my WRX tranny and when i was talking to the dealership they were talking about a new OEM 6sp(thats not the current ST-i tranny) but it was 7K from Subaru. FUCK THAT. If your looking for a stronger transmission you can build up a 5sp thats just as strong for less than a conversion. Also if you plan on drag racing the car i wouldn't even worry about a 6 speed. When the ST-i's were first being tested against the EVO's they ran slightly slower 1/4 times because of the 6sp vs the 5sp. The ST-i had to shift one more time than the EVO did and that can cause some loss in time.

i would just build up a 5 speed tranny. I actually still have my blown out transmission sitting in my garage if your looking for something to build up. Than you can just drop it in your car, or wait till your 5sp pops and than put it in.