Legacy GT 4/2 pot calipers fit SVX

[Jvan]

The title is my question. I was searching other Subie site for a brake upgrade for my SF5 Forester and came across an Ebay listing for a Legacy caliper that claims the caliper also fits the SVX. I haven't researched the part numbers but if they are the same caliper then would swapping the front/rear to GT 4/2 pot calipers make a significant brake upgrade?

['E']

Are they factory subaru calipers?

[Jvan]

The eBay listing is for a company that rebuilds the caliper so i don't know if they are OEM Subaru but the listing shows that the calipers are used on a number of Subaru's (Including Impreza's) and for several years : http://www.ebay.com/itm/380582743128?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649. None of the listings show a LGT so I don't think they fit the newer Legacy's, as I had hoped.