Anything special about a 91 318?

I'd say what sets the 91 teen apart is the roller cam. That's about it. The heads are arguably not better than the LA heads, just different. So, IMO the roller camshaft is the only real "upgrade". People can disagree all they want, but in stock form, the heads have small valves, tiny, unworked ports and small bowls. The heads certainly have potential, but in stock form better? I say no.