I personally recommend against any form of "dicking" with an HK trigger.
I had a USP in 9mm. The trigger was stock. I got the bright idea to try and install a match trigger kit that I bought on the EE here. HK disassembly/reassembly (particularly the trigger group) is very tricky compared to something like a classic SIG or (duh!) a GLOCK.
I got the gunsmith at my local shop to give a shot at installing it. It came back firing, but wack. Then I took it to Joe Dlask, who fixed it and got it alot better (than the wack version) but it still wasn't quite perfect. All in all, the best trigger was the one that it came from the factory with.
I bugged me, so I traded it for a P2000 (to my local shop, they were aware of the history). This was a few years ago.
Recently I traded for a USP .40 - one of my conditions on the trade was - the trigger must not have been disassembled or dicked with in any way.
I feel completely comfortable detail stripping a classic SIG - polishing the sear or whatever... but with HK... once they come apart, they are never quite "right" again. At least that has been my experience.
"HK certified armourer" means #### in my book. I would want the actual HK factory in Germany doing it - and realistically that ain't going to happen.
My advice is just learn to use the trigger that the gun comes with. If you really can't get use to it - get a different gun. If you want an absolute bomb-ass competion trigger, super light, crisp, short reset.... 1911 my firend... all the way. The USP/P2000/P30/HK45 guns are duty pistols through and through - designed for maximum reliablity. You can't make them into something they are not. Enjoy them for what they are.