My 2005 GM Ultimate Edition just broke into 20,000.00 miles. Got her with about 9,000.00 on the odometer about a year ago.
Best upgrade mod was installing a in dash rear view camera system with blue tooth.
Hands free phone system and rocking to Pandora Kid Rock "I'm a Cowboy" is awesome.

Installed all new shocks... New slotted and drilled rotors with ceramic pads.
Dual exhaust with stainless tips.

18 inch black rims and wider tires....
Ceramic coated the exterior paint....
Dark tinted all glass

Ford dealer was amazed ....

Good luck with your mods.... these are amazing cars.
I came... I saw.... was not impressed