Want to swap my sl1 sohc to a sc2. What is the best year dohc engine for performance and
Transmission combo that will work and what if anything else it may require to complete this task. Thanks.

 

They all perform near 100% the same. Go to the link named "Swap Questions" and have a read. Also search the internet for the Saturn Swap Guide. No idea what year car you have now, but in most cases you'll need everything including wiring harnesses and computer.

Having a donor car would be the way to go.