I added a SW cockpit a few months back, had my SW UR pending sale, so i had time to compare firsthand.
The Cockpit only has a 19 inch amp (elusive 25 inch!), while the UR has a 19 inch WG6100.
Both were freshly capped. At first, they look nearly the same. In fact, i was a little disturbed at the similarity considering the hype amps get. Its during game play where the Amp really shines - it feels "faster" or able to keep up with the sprites better. The lines are also smoother and crisper, with the WG i could a little more jagged edges. Colors are about the same though.
After playing a few games on both, i could see the difference.
Amps are cool. I think to the OP question - at least 250+ increase. Amp set ups alone cost more than that - amp monitors are easily 150+, board sets 200+.