A999 as a street/strip trans.

I had a 998 built up with a performance TC and stayed with the lock up. Set up to shift at 5200. The unit you may have is hydraulic only operated lock up no electronics or solenoids involved. It locks up at about 40-45mph and works good,lowering rpms and has a real 1:1 feel to it like a 4spd. I would not eliminate it on your 999 which is
a heavier duty unit than the 998. I have to add 98mph is not doing well with the combo you have.