When I had my 33 It had a gutted cat and it used to shoot flames! Ha ha, the only reason I gutted it was the fact the inside fell apart, was a 3 inch nismo cat, only had two sections of substrate in it, both around 4in thick, one had broken away, rattled like a b*tch.
Back to the question on hand. Get some Selleys 401 Hi Temp Sealant/adhesive to seal up coil packs or spend $600 and get some splitfires.