It's time to but a new gun and I've pretty much zeroed in on the USP Tactical in .45.  I can get the gun NIB for $850.  After reading up on the gun though I got to thinking would it be cheaper to buy a full size USP and replace the barrel and trigger so that it performs like the Tactical?  I don't ever anticipate putting a silencer on the gun but I would like to have the O-ring barrel and the match trigger.  

Are there any other differences between the guns that I am missing?  Is it possible to buy the O-ring barrel and match trigger and drop into to a standard USP?  I don't care about the adjustable sights either as I will be replacing the sights with night sights.

BTW I can get the USP for $625 NIB or ~$500 used.

In my opinion just go with the Hk USP 45 and save your money.

If you do not intend on buying it to use for use with a suppresor
then the threaded barrel is not worth it.

The O ring is nice but not really neccesary.

You get a match triger with the tactical. I have both and prefer the tactical - it seems to be a bit smoother.

Quoted: In my opinion just go with the Hk USP 45 and save your money. If you do not intend on buying it to use for use with a suppresor then the threaded barrel is not worth it. The O ring is nice but not really neccesary.

Yup, I agree. as far as smooth, just shoot about 500 rounds or so, it'll smooth it.

If you want a Tac, buy a Tac.  NEVER buy a USP with the idea that you are going to save money by doing the converion to Tac yourself.  First of all you end up spending about $150-$350 extra doing the conversion yourself and second, you end up with a tricked out USP, and a tricked out USP is not a Tactical no matter how you dress it up.  It will not say "Tactical" on the slide and if you sell it you will not get Tactical prices.
New USP $625
Tactical barrel-HK $300, after market $240
Match trigger-$125 plus installation
Match sights-$135
Soft case-$75
Cleaning kit-$25
4 extra o-rings-$20
Total:  HK barrel $1250, after market barrel $1145.  Used gun $1020 at the cheapest with after market barrel.
NIB Tactical $900 from many on-line sellers such as Bachman Pawn and Gun, Dallas TX.