I honestly think you aren't going to get much more out of your current tires. It's not the same as an N/A V8 (with similar power) where the power is smooth and predictable and you can squeeze the throttle off the line to prevent wheelspin. With a TT that burst of power during spool is always going to break traction no matter what you try short of an EMS with progressive boost control and 5lb wastegate springs. I still say go with slicks for your axle's and drivetrain's sake. Even M/T doesn't recommend their DR's for manuals.