Quickspool does not imply the GTT300 is laggy ...far from it as Lee and I know. 280Tqs will use a smaller turbo though ,boost threshhold will be in the order of 500rpm earlier.
There would be an upgrade path from 280T qs to 300T ,but would mean buying 2 turbos and 2 intercooler setups etc. ...We can do it though.

Al....I would anticipate the first conversions requiring the car 3 weeks ,reducing to 2 weeks once we get in the groove.