Have a set of Bozios being pop tested and installed..any input to improve performance??

Injector Pop test@135bar
Injection Pump Timing Advanced@27degBTDC

It will regain any performance lost due to injector wear but you won't gain anything over stock.

Any recommendations on timing advance?

26-28 is a good range.

Thanks forced..always coming through..care to expand on the science behind it to make the thread worthwhile??

Advancing the timing makes the expansion pressure peak closer to when the piston starts moving down, which increases torque, and allows the gasses to expand longer, which increases efficiency.

If you go too far it starts expanding before TDC and the piston has to try and compress the already expanding gasses, which will stress the headgasket and hurt power output. That will sound like shaking a bucket of nails when you accelerate and the engine will be hard to start.

MB had to meet emissions at the time and retarding the timing lowers combustion temp and NOx production.