The symptoms persist after the car has cooled off and sat for multiple days. The only way to restore normal function is to "exercise" it. I can go for thousands of miles between flare ups, so I don't think there's any air in the system. Also, if there was air in the system, I would have issues...
I have an RST with an MGW and BG fluid. Occasionally, and especially after multiple high rev shifts, shifting into 1/3/5 becomes difficult, almost like the gates become triangular (ie, the resistance increases as you push the shifter further into 1/3/5) and it becomes harder to tell when you're...
Does it still have the clutch pedal assist spring in it? Taking that out (or swapping it for the Steeda spring, if you are intent on spending money) helps with the overall feel.
If you're not willing to "get a whole suspension kit", you're going to have an undrivable 900 hp car that is going to sail over a sidewalk and through the bushes. You don't need to buy a kit, per se, but you need to look at the supension holistically rather than from a "I don't want wheel hop"...
Dude, I have the whiteline bushings. Everyone has different thresholds for acceptable NVH, and a surefire way to increase it is to mess with the diff bushings in any form.