Looking to fit Samco Turbo Hose kit, but there seems to be two different kits, one with 3 hoses and one with 4.

Mines a MY01 WRX with an STI intercooler fitted, which kit should I buy?

And where does the extra hose go in the 4 piece kit?

 

AFAIK STi intercoolers have an alloy 'Y' piece underneath so this kit comes with 4 hoses. Turbo to bottom of 'Y' piece, 2 for the each end of the 'Y' to intercooler and intercooler to throttle body.
Could be be wrong though, going off memory on my old STi 5 and probably similar for the newage.

The WRX only has 3 as it replaces the plastic 'Y' with a silicone version.

 

Cheers Richie, you're right.

I've ordered the right one then. (for a change!)