Sorry, I've no recommendations for a shop as I haven't any personal experience with any I would recommend.
I will say that Kahr offers sight installation:
http://www.kahr.com/Upgrades-and-Ser...ce-CS-ITEM.asp
The front sight on the CW45 is DIY friendly as a replacement option. I've found the Trijicon sight works with the OEM rear sight. I imagine a sight of similar height from Dawson would work as well.
The front sight just snaps off (poke out what remains of the posts):
If you want to go DIY with an after-market rear sight, getting the OEM sight off can be little challenging, but can be done with a punch, hammer, and solid vise. The new sight will probably require fitting with a file, sand paper, or stones.
I'm not a fan of paint over stainless, as I don't like how it wears. I think for maximum durability paint is best done over fresh parkerizing. Others may disagree, so it would be good to hear their input here.
I'm going to flesh this reply out with a few more CW45 photos:
Regards,
Greg