Personally I'm going to be getting a spec stage 4 which is actually a spec stage 3 with a rigid hub. The stock 4 and 6 cyl will probably slip under acceleration. This is assuming you were talking about installing a clutch that would accept a s/c 3800. If you're talking just about what you're wanting to run your 4 cyl for a while, I'm not sure if the 4 cyl would work on a getrag since the 4 cyl never came with a getrag. Someone will definitely know the answer to that. Just for your info, here are the spec stage clutch numbers and max torque.
Stage 1 - SC881 - 250TQ max
Stage 2 - SC882 - 310TQ max
Stage 3 - SC883 - 450TQ max
Stage 4 - SC884 - 450TQ max (rigid hub)
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[This message has been edited by JamesCurtis (edited 03-07-2008).]