I have used them two times to have the slide refinished - Shipping is expensive to ship the entire pistol (you will have to send it next day). Shipping ONLY the slide is much cheaper.
As said above, it is $45 to refinish the slide. U should call them and speak w/ them, but usually U just send it to them, and include a note w/ your information and what you want done - I think U can either include your credit card info on your note, or tell them via telephone.
If U want your gun "upgraded," you can send the whole thing in, and they will replace all of the springs and stuff - but you really are paying it since you have to pay the shipping.
Also, I would not recommend buying night sights from them - Last year, I had a G26 slide refinished and had night sights put on it - when I got the gun back, the sights looked terroble - the white circles around the tritium was all messed up. I complained, and they paid for shipping back to them. They then called me and said the sights were w/i factory specs and they would not replace them.
When I got the gun back afterwards, it looked like the rear sight was replaced, but it still didn't look that great.
If ya want nights ights, buy them locally where U can see what you are getting. Then take the slide and the sights to a local smith for install.