Nothing else but a CG10 or CG13 is a direct bolt in replacement. GA16 and SR20 are possibilities with lots of mods required and these have been covered before. I'm sure just about any 3 or 4 cylinder could be fitted if you're prepared to do all of the hard work and then have it engineered... I think it would be cheaper and easier to have a CG posted to you if you can't locate one locally.