They are not. They had their Illinois license revoked for about a week back in May.
https://www.kbb.com/car-news/carvana-can-sell-car-in-illinois-againwith-limits/
Fine- The trans makes more of an impact on street driving than the converter will. I don't think you'll run into a situation on the street where you're stalling the converter at 4k rpms.
I've got here a p2uned methanol bracket. The same bracket I use in my car for Methanol Injection. Needs hardware, but you can grab that at any Ace Hardware/Home Depot. There's nothing special about the tank bolts.
I'm literally trying to get rid of this stuff, so make me an offer.
Images...
Do it. I regret having to pull the trans again. If you're looking for high-stall, you should do it while the trans is out rather than have to do it twice.