the way i see it you have a few options. really depends on how thick your pockets are. stick with the stock engine, add a sprintex. cost if not mistaken 10k, getting a cfe engine in good condition is tricky. if even if u can find one, you are gonna need with full set wiring or run a standalone and wire it up. a good job would be very expensive. other options is like what others have suggested. 4g93 either turbo or na up to you. i think full cost of transplant may be more than 10k. In my opinion, a sprintex kit sounds good. u have an engine of known history and lesser future headaches. although 4g engines are pretty bullet proof, they are old. parts will soon be an issue. like others mentioned 4b11 not even worth the effort. all the best man