NooB question and LS6 in 968?

Will a bone stock LS6 (complete with factory headers and emissions equipment for CA smog) fit into a 968 without issues? Anyone here have an LS6 968? Do the factory headers fit in the engine bay? Assuming all LS6's came with dual exhaust from the factory (right?), is there room to keep the factory cats etc. under the car, and then tie it into a single exhaust? Is there a reason that LS1 conversions seem more popular -- other than the cost of the motor?

Welcome.
No, the factory headers won't fit without major chassis modifications.
Most do a dual in to single exhaust, some have put true dual exhaust all the way down too.
Yes you can squeeze the cats in place for emissions, quite a few have made Ca smog compliant conversions.
Do a little digging around our site and you will find answers to all of your questions; if you don't find the answers you need there are plenty of experienced folks who will likely have the answer.
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I would guess that the popularity of the LS swap is likely down to the fact that it is the most compact of most V8s offered (Push-rod Vs OHC), makes good power, and is in plentiful supply.....

Thanks, will poke around here as suggested. In the meantime, are there CARB-approved headers known to fit in a 968?

No, If you would like to Help with the cost of getting my headers to be certified, then they would work for you. (Cost or certification is in the neighborhood of about $50k ) You'll have to wing it and hope they don't call you out on it. You would need a stock manifold, but it would still need to be modified, just remember once it's modded it'll no longer be truly legal either....