I finally got a day off when it wasn't miserable outside! Here are a few pics from making mine. I used conveyor belt material from Industrial Conveyors (Rubber Bits) in Petone (Fitzherbert Street). It is 5mm heavy duty rubber with a canvas mesh insert, and at $70 a square metre, is waay cheaper than Urethane. I got a piece that was 1200x600 for $50. I've cut three rears and two fronts, with enough left to get one more each for front and back.
I bought an old perished and cracked set of STi ones off WRX8YA, so I had mounting plates, and some really good templates
And this is what it looks like with all four