late model twin cam swap questions

[sl2clone]

I am only going to ask questions here that aren't answred in the sticky. Or I believe they are not in the sticky. I have read through it mnay times trying to soak in as much as I can.
The engine going into the clone is from a late 99 with CA emissions. The engine has the stupid pre-cat in the manifold and the 9 bolt configuration on it and it also has the inlet for the air pump. My single cam engine doesn't have the pre cat nor does it have an air pump on it which the other car did.
Now did any of the 98 or 99 SL2 models come with a twin cam engine and no electronic air pump? I want to TRY to avoid the SES light coming on. I don't want the PCM commanding or looking for a non existent device that my car isn't even wired for nor would I ever connect and install such device. If what I am looking for does exist does anybody knwo what #sI would need to look for on the PCM or just call the salvage yard and tell them I have a 98SL2 with federal emissions and a manual trans?
Does using a new OE PCV valve really make that much difference? The enigne used 1 quart every 2K miles when I got it. WHen my GF crashed it it was up to 1 qt every 1K if not more. I have it doing an extended length seafoam saok while it is out of the car. The the engine will get flushed with ATF and light weight oil for a few hundred miles.
Are there any other issues I should look out for? Welding is no problem at all. ANyting I need to make I can with ease. I just want to know if therte are any bumps top watch out for. Seems mostof the swaps done were earlier models than mine.
Has anybody seen a twin cam leak oil from the head gasket?