I haven't seen the coolair one, have you seen the JK 4:1 stainless? I've got one, so did hailfrank good bits of kit.
i'm getting one of these http://www.vintagespeed.co.uk/index...tegory_id=27&option=com_virtuemart&Itemid=119 obviously, i wont be fitting it
I have seen the JK one, the cool air is a little cheaper, I'm just unsure how much is sticks out below the van Cool air JK
Theres also the bluebird one to consider http://www.bluebird-type2.co.uk/split bay exhaust 1500 up.htm
This is a video of the JK exhaust in action .. The towbar means the rear bumper is further away from the valance so the tail pipe looks short. It hangs down about the same as the underside of the engine if you make sure its bolted on level.