The 5" XD40 Tactical wouldn't be a bad platform to start with. I don't see any 4"ers at USPSA matches except in Production. They would be considered handicapped due to the shorter sight plane and the slight velocity loss. The service model would be challenge to use at 15 yards and out. That said here is what I would have done.
1. Bomar combat rear sight mounted low.
2. A Dawson or Hi Viz fiber optic front sight.
3. A good trigger job.
4. At least 5 Hi Cap mags with pierce extensions(for Limited). The more the better.
4a. A Magwell
5. Competition holster like Houges or CR Speed with 3 competition mag
pouches. CR Speeds belt systems are the best and are must haves.
Thats all that pops to my mind right now...hope it helps some.
1. Bomar combat rear sight mounted low.
2. A Dawson or Hi Viz fiber optic front sight.
3. A good trigger job.
4. At least 5 Hi Cap mags with pierce extensions(for Limited). The more the better.
4a. A Magwell
5. Competition holster like Houges or CR Speed with 3 competition mag
pouches. CR Speeds belt systems are the best and are must haves.
Thats all that pops to my mind right now...hope it helps some.