haha if you want one, i got one loitering on my driveway waiting for a good home =P
apart from that, i love how the 2 look tho haha, i still cant get enough of watching the FC go off. mine is white so at night, its amazing to watch. =P
It’s totally possible to do that swap. Any swap is possible if you have the money to spend.
The 13b though is a very tough engine, a few little things and your making serious horse power. It’s also the only engine I’ve ever heard that almost guarantees 50hp from a port job. There’s no n/a engine that can boast that. Main issue with those engines is the apex seals going due to the extreme heat put out by the motor. Replace those, do the port and dam if you don’t have yourself a very fine running car.
The 20b’s are of course a stronger running motor, handle more hp and can be beat on while asking for more. They are “apparently” a very easy (but expensive) swap in to FC’s but not easy (and MORE expensive) in to FD’s. Plus for the money you’d spend buying a 20b, put that in to the 13b and make an easy 400+ hp to the wheels!
If you have the money and your hart is set on the SR20, go right ahead but make sure your doing it for the right reasons and not going on “things” you hear. Like anything else do some research, ask questions and then decide.
Good luck man.
Cheers 
i say jus custom ur engine.
FB with a 12A + single barrel webber carb + tuning = 220hp 2300lb RX-7
now that would be sweet.
lol my friend wants to rip out the renesis bullshit in my RX-8, throw in a 13B REW and a nice big turbo haha should be interesting, sadly it isnt likely to happen since the car is on lease haha
Mazdaspeed does not supply or have any 4 rotors. Unless this is something that just happened within the last 3months.
I had an '06 shinka for a very short while, and IMO, the renesis is a superior engine. Sure it doesnt come boosted, but once ppl figure out the ECU, I am sure it will be a beast.
IIRC, to swap a 13b into your 8 would be a waste, for the money you might as well go 20b and boost it to 600whp. Just like the guys in PR.