Question about about Donahoe lift

[ALEX Bronco]

I just had acustomer call about a truck he wants on Ebay.It is a 2006 F250. The price is right, but it has too much lift to be legal here. It is advertised with an 8'' Donahoe lift. On Donahoe/ Icons sight, they list a 4.5 and 7'' lift , with the 4.5'' being upgradable with some minor parts. My question is, can be go backwards easily to lower it 2.5"?
This is the truck. Thanks.
http://cgi.ebay.com/ebaymotors/06-Ford-F250-SPORT-FX4-Power-Stroke-Diesel-Monster-1OWN_W0QQitemZ350022102042QQcmdZViewItem?hash=item 350022102042