Time for a rebuild to get rid of piston slap (worse than it should be, always there a little)

At the moment the cars only running greens & 3bar

Gonna go to T34 and maybe a live map on greys or similar.

If I don't plan on going past that point is there any point of going low comp??

Anyone know how much 4x4 piston lower comp by when fitted to a 2wd and are they a direct fit?

Edited to add opinions on long studding too please!

CheeRS