FE3 or even better the Kia licensed version from the 1st gen sportage (already longitudinal) would be great for your car! There was a guy who took an bored out a Sportage FE3 and put in an F2T crank to make it a 2.3L. He then turbo'd it for about 400hp and dropped it in a Miata. That would work nicely in a RWD P5!