I would use a 20b mazda engine ,none bridge port before the Suzuki. I know the motor cycle engine is very popular though. Another good option is a sbf,like the coyote crate engine.
All of the swaps start with more hp than the original 6 could hope to supply.I also thing the 20-b ported sounds nasty,and it has enough rpm to make it sports car like. W/E you decide,its yours and different.Make sure to post some pictures when its close to being finished,and enjoy the project