Need some advice regarding exhausts. I own a 94 Cav GLS with the Ecotec 2.0 16v block. Now the exhaust downpipes are fairly knackered. I have a combined manifold/downpipe from the older calibra 2.0 16v (non ecotec) or the same from a Jreg Cav GSi 2000 16V (non ecotec). Will the older combined manifold/downpipes fit my Cav with the ecotec or are the exhaust ports & studs differently aligned? It will save me some much needed bucks!