Hi Scotty... do you have a fat wallet and / or some good engineering tools / skills?
It can be done, anything can be done to a cost, but you need to plan, think about what needs to be done, what motor etc, & what to do with suspension & brakes? What will the insurance be on a modified car?
Why not just buy a bigger engined car in standard form? Less hassle, quicker, cheaper to buy & insure... & probably a better car at the end. Not knocking the Sei but clearly it has something lacking for you....
I see from your Blog that the current motor may be foobarred... & that it is too costly to fix... almost eliminates the chance of doing a bigger engine transplant IMO.