According to HD specs the 2013 FLTRX has a seat height of 27.1 inches and the seat height on a 2008 FLTR is 29.5 inches both year models have a ground clearance of 5.1 inches. You have to keep in mind that the 2008 FLTR came stock with the big thick touring seat that come standard on the Ultra Classic and not the low profile seat that comes on the 2013 FLTRX, after changing the seat on the 2008 FLTR to a low profile seat you come up with around the same seat height you would on the stock FLTRX. I use the HD low profile leather bucket seat on my 08 and I sit pretty low and it is comfortable as well. The big factor is the ground clearance 5.1 inches is not a lot of clearance so lowering the bike takes away from valuable ground clearance. JMO
08 FLTR candy red sunglo,with 2015 103 HO, V&H Dresser Duals with Monster Rounds, Power Vision tuner, Willy Shiny Wheels and Forks and a bunch of other stuff.