Out of all the options, I would personally go for the 3S-GTE. Bolt-ons are a-plenty. You can go up to around 400 bhp without opening up the block. It's lighter than the 2JZ, 1JZ and their turbo relatives. Being a 4-pot, you'll have enough space for a good cooling system (although the stock rotary cooling system should be good too, rotaries are notorious for heating up coolant), and a good intercooler. Soundwise it'll be a bit non-descript of course, but hey, a snorting turbo and fluttering wastegate are as cool as N/A induction roar. I've got good experience with a 2JZ-GE VVTi and a 1UZ in the process, and I wouldn't recommed either for the RX-8.