Can't comment on the Colt match barrels, but I've had guns with Kart barrels and non-match barrels. On a rest, shooting from a sandbag etc. you may see a slight improvement in accuracy but in the hands of us mere mortals shooting off-hand I've found them to not make much difference.

kind of what i was thinking

Considering the price of the Kart Match barrel ($150), compared to the price of the barrel already in the gun ($0), if there isn't a noticeable amount of improvement, I don't really see the point.

Colt's barrels are quite good,but they're fit on a production line with drop-in parts in general.IF you have good lower lug fit (and upper,push down on the hood after lockup),the basics are there.Rebush the nose and it should shoot better than most can do.I like EGW's cut to my barrel OD and the largest ID of my slide to work it in.

If your barrel is loose in the rear,Kart is a very good choice.They aren't real hard to fit if you know what needs done,but it can be tedious because it's easy to go a stroke too far on a file.They have an easyfit and a fitting tool kit that works out great on any close to spec gun,and with the instructions and a litle research on proper fit it's basically a kitchen table gig depending on your mechanical prowess.If you're going to have a real smith do it,a full gunsmith fit is ideal.Your sights are mounted to the slide so the barrel needs to index the same every time in the slide and sit on the slide stop, .010" rail movement slop is basically negated now and it will shoot as good as you need until you need a bullseye gun or frame mount the sights.

what does rebush the nose mean?

Sorry,it's fit a new bushing to the muzzle and slide,the PM reply explained my perdicament last night

If I remember right this was a 70 series but don't know if it's an original or the new reproduction.Either way the new barrel will be fit better than original almost guarrenteed so mechanically it will be more accurate.You do have stronger barrel now though since Kart doesn't use stainless steel,a kaboom will ruin both but stainless will split open much easier.