i'm sure this isn't a problem for you, Pat, but... if you buy your sights from here:
http://www.shop.xd-hs2000.com/Meprolight-Night-Sight-for-the-XD-Pistol-MAK11410.htm
You just send him your slide, and he installs them for free. The XD sights are notoriously a damn bitch to change, because they're tight as hell. He does it for you. When mine came back, it was dead-nuts centermass on-target at 25 yards. Point Of Aim IS Point Of Impact. He nailed the installation perfect.
Me: XD-45 LE Service Model (LE has the thumb safety) with a Springer Precision trigger kit, Springer Precision extended mag release, Meprolight tritium sights, and Streamlight TLR-4 light/laser combo. During the day, without light, it rides in a Mernickle PS6 High-Ride concealment holster. Waiting on a custom kydex holster to use when the light is on it, and that's coming from these guys: http://www.kt-mech.com/
Also rocking the XDs45 since it first came out, and it just runs in the XD gear holster that came with it. It has the Powder River Precision trigger kit, extended mag release, and extended grip safety. Very satisfied with this little bastard.