3sgte swap into an rx8 Options

[Malhar95]

[Story]
My other car is a mazda rx8, sooner or later i know its going to need a new motor. And i'm not at that level of learning and understanding everything about a rotary to build one(or get one built and manage it correctly), so i was thinking out swapping a piston engine into it (getting it done by a shop ofcourse, maybe ATS or DDperformance, but havent decided yet).

My first option was a LS swap, because its 'murica and we like v8s.
But then i would prefer toyota since im more familiar with them...so i thought about 1jz/2jz. I know theyve been done to million rx7s and few 8s, so there are some off the shelf partially ready swap kits for those.

But im not looking for that much power, maybe 300 whp for now, and later upto 500 once im used to power.
so that being said, i figured a 3sgte would be a good candidate since its EASILY capable of that power, im familiar with it. And its also going to be smaller, so less weight going towards the front, so closer to stock handling (comparing to ls and jz) and lighter too.
[question]
But i havent been able to find any swaps similar. Im trying to find a transmission that is going to work with rwd. from what ive read, the 1jz mounts to the stock transmission on the rx8, so is the 3sgte and JZ have similar bolting points? If so i can just use the stock one.
Also, any suggestions of how to tackle the exhaust problem, the 3sgte exhaust side faces the driver side, so its opposite to both the stock 13b and JZ, so the turbo might not fit. I was thinking of doing a semi-rear mount turbo if thats an issue.

last question, i read alot about people running two seperate ECUs to run different engine. how does that work?

does one tell the engine what to do and the other the dash?

If you guys find any builds simliar to this or have seen it in person. i would really appreciate some suggestions/tips
Also i know "anything is possible if u have money" that being said, i was quoted 11k for a LS1 swap out the door.
so im hoping to spend equal if not less for this swap.

[Smaay]

I would NOT put a 3S-GTE in an RX8. Its not a cost effective engine. you said yourself you only want 300 something, well a stock 2JZ will do that. then turn up the boost when you are ready for more power. Just because my Supra makes 1000 HP does not mean I run it there all the time. I turn it way down. ill make 600 for normal driving and thats stupid fast.

I would also consider a Toyota V6 option. since the 2GR has RWD applications, finding a transmission that will bolt up shouldn't be an issue.