Very nice pistol.
As far as I know, the various metal grip safties on the market will not retrofit to your gun...although I am sure there is someone who possibly could make it work if you have the bucks. The plastic one works just fine in mine (Ultra) and I have learned to live with it.
You can find sights cheaper at several vendors, but who is gonna put them on for you? Remember that if you do it and break a vial (which holds the tritium) or scratch up the finish, etc. you own the sight install...so you get to buy another or pay for a refinish. The extra few $$$ spent for someone who has the correct tools and fixtures, and knows what they are doing to install sights is well spent.
Para mags will not work in my Ultra, but they appear to be very close to fitting. Since I no longer have anything except one old Para 10 rounder, it is not worth my trouble to try and make it work. Kimber high caps are still out there, you just have to look harder.