Just heard from a guy in Vancouver who has a twin turbo C6. He says Corvette Specialties, going to check them out!You could try EVOLUTION AUTO Performance in Maple Ridge.
Evolution Auto | Evolution Auto Performance - Maple Ridge Performance and Dyno Tuning
I see they recently tuned a Demon to run 9.7 with the stock blower.
I have not dealt with them first hand but they seem to be turning out some quick cars.
I supercharged my C7 with a Magnuson and also had the same issue with the misses. I used a local shop in Winnipeg but I had them working with Davenport who help figure out the issue. The lesson to learn is there is a bunch of trial by error that needs to be done in order to really fix it as the issue for me at least was bad wires. Started off with replacing plugs which seemed to solve the problem for a day or so and then we thought it might be the tune so replaced the plugs again and checked the tune and all was good but started to misfire late that day. Next replaced the plugs with the Granatelli 0ohm wires and coil packs and problem solved. The people at Davenport seem to really know their stuff and all the not the most optimum they will work on the car remotely.Hoping someone can steer me to a well known C7 Corvette performance shop with some experience with supercharged engines please.