[SCOTI]

I don't know about the 'how much' question but I know of @ least 2 guys here in TX that did a LWB to SWB frame shortening in apartment complex parking lots by hiring local certified mobile welding guys to weld their frames. This was w/o kits like these; these type of kits would only make it easier to ensure proper cuts & alignment.

A corporate body shop chain probably wouldn't do it but a local independent body shop or welding shop would be the better choice. It won't get done on the cheap though. I would expect a minimum of 3hrs time charged @ >$100/hr labor rate (shop space, the experienced guy doing the labor, consumables, validating fit, equipment set-up + their profit margin).