If I were to do a complete engine swap I would do an LFX.
I love my supercharged (MP62 Roots) 1.8. Big throttle body on the 'charger inlet, 550cc injectors w/Megasquirt, flat top intake manifold, Mazdaspeed 4-2-1 header, Roadster Sport midpipe w/high flow cat and RB dual outlet muffler. I am in the process of swapping cylinder heads to one that is ported/polished along with a JDM intake cam (would be done except for illness/cold). We'll see how that changes things, but as it was the off-idle grunt was great. Always felt like a bigger engine in response and driveability. The sound as the supercharger spins up is like no other. Looking forward to seeing how it changes with the new head.