High Country Nomad
Mountain Explorer
No, the factory LR 18" wheels off the LR3 will not clear the front Brembo calipers of the 2006-2009 Sport Supercharged, unfortunately. The Compomotive PD1880s - I think they have a new model # PD1881 as of early this year - will fit however (you may need to flip around the anti-resonate weights found on the Brembos to get them to fit.) I doubt even the 18" Compos would clear the larger brakes of the MY2010-13 5.0L Supercharged though - although I am not 100% sure if anyone has tried that combination yet.
As far as tire size, I ran 285/60R18 A/Ts on my non-lifted 2006 Sport HSE for years, with very negligible rubbing only experienced under full compression or steering lock, which would kinda disappear on its own as the tires wore off slightly after a few thousand miles. That's as large as you can safely go without and modifications / lifts. A matching spare of that size will fit under the car, but only if partially deflated - and you may need to get rid of the heat shield between exhaust and spare tire to winch it up without issues. It will be a tight fit.
Here are the Compos mounted on a pre-2010 Supercharged with 265/65R18 BFGs (they will also fit without mods and with only minor rubbing, but you will have to store the spare elsewhere, no way to squeeze it under the car):
Do you think 18" wheels of an 0'3 D2 would work on an 06 RRS HSE?