http://www.ebay.com.au/itm/3-VENOM-High-Flow-Metal-Cat-WRX-XR6-Turbo-Skyline-VL-FPV-F6-GTR-S15-S14-SUPRA-/250992961913?pt=AU_Car_Parts_Accessories&hash=item3a7058a979#ht_3581wt_1037 This is the cat I have, it works a treat. Other wise there is a group buy going on for Ballistic cats. Both will have to be welded in, if this is an issue get a spare cat pipe from a wreckers and get it welded in that. Cooler pipes on B series should be fine, FG's is where the pipes become an issue. Keep an eye out for a second hand Process west or plazmaman stage 1 replacement coolers if you really want to keep costs down and retain factory looking engine bay, they come up all the time. You'll probably need a walbro gs340 fuel pump too then.