If you are running port injection with stock turbo you should have more than enough fueling to run full e85. Find a tuner you like and hit them up. Both Marin and Twisted tuning are on the forum.
I did the maxton front lip and love it. The kit looks good on your car but the red accents isn’t my cup of tea. I actually wished the black was a better match for the satin black factory trim pieces
e50 tune/flex fuel + downpipe is about $2500 USD good for 500whp/600tq
Next step up would be Pure800/Flex fuel/Port injection. Probably $7k+. Easy 600+whp, but you'll be limited by transmission ($3500+) and axles.
sometimes the labor of swapping them is more expensive than buying a spare set. Im guessing the shop is trying to avoid pulling them out of your old wheels.
I dont see how the JB4 can add additional fueling. Unless there's a map that Berger tuning has for e50, I would not run it since it cannot compensate. Could be a bad combination.
Several of my local guys run e50 or flex tunes. No issues really, but most of us will run 93 octane only from time to time. The only real noticeable thing for me is that my car starts up slower if it sits with e50 in the tank for more than 3-4 days.
I shopped a lot of used wheels and the only thing I can say is there doesnt seem to be many MB/Audi aftermarket wheels that have good offsets to work on the Supra. Bore can usually worked around with a centering ring if larger.
stock charge pipe will hold fine. Had the same conversation with my tuner and he's done plenty of tuned cars and recommends to keep the stock one unless i need meth/NOS nozzles or port injection. The older bmw were notorious for collapsed charge pipes, but the supra ones are fine.
IMO this is probably one of the best sounding exhausts on the market. There’s another white 2020 in central Florida that was at the dyno same day I was back in January and it sounded almost like a 2jz with the boostin exhaust. Nice choice.