Some Advice for a 01 altima

I own a 2001 nissan altima gle. I wanna do some upgrades to make it faser n possibly do an engine swap. i wanted to know what are the best upgrades to do and if i can do an engine swap what could i swap it with? I forgot its a automatic. Also if anyone knows or has a yellow top for a 2001 alima and could tell me which one i need to buy that be great.

buy the turnado