Not sure what you mean by "trigger job" but hope this helps:
I put a lighter hammer spring (Wolff brand) in my GP-100 .357. I didn't like the heavy pull in double action and this change made it very nice.
I didn't think the factory trigger action was any less smooth than other revolvers so I didn't do anything besides the spring.
The kit was only $12 and contained three hammer springs and two trigger.
A little tricky making the swap, but once you grow a third hand it goes easy!