would an ecotec fit in a 96 sl1 with out alot of problems?
Not really. You would need a few things.
transmission, ecm, bcm, newer fuel system, underhood engine harness, dashboard harness, engine mounts, trans mounts & new guages
These are just some things, theres probably alot more.
I'm not sure if the mounting points on the frame or even the same.
You could though swap out the 1.9 SOHC, which is what's in a SL1, for the 1.9 DOHC....