Thats a can of worms but here are a few....Trigger job, barrel/bushing, tighening the slide, extractor/ejector tuning, springs/guide rod, custom sights, etc. the sky's the limit. A competent gunsmith will be able to go over the entire gun and break it down for you as far as your needs and your expectations. I had a very notibale gunsmith known for his IPSC guns. With gunsmithing, you get what you pay for and you will get on a waiting line to have work done. For me it's all about accuracy and reliability. I shoot out to 50 yards and if I can't stack bullets with a 1911 at 15 yards there is a problem. These are the most enherantly accurate automatic pistols and they really can sing with the right nip and tuck.
Since Colt has never made a hi-cap, your experiences with Colts in Limited competition must be almost twenty years ago?
I bought a new Colt in 2004, for IDPA competition, but the gun is also legal for USPSA Single Stack, and other than installing an ambi safety and a fitted bushing, it's good to go. And it's the cheaper "1991", not an XSE. I wouldn't trade any of my Colts for anything Kimber makes.
Kimber fills their $1500 guns with $5 parts, and stamps "Custom" on them. If they spent as much money on their guns as they do on full-page color ads, I might be interested. I will give Kimber credit for making other 1911 makers up their game, but that was ten-fifteen years ago.