2004 Chevrolet Tahoe LS Rwd 4dr SUV (4.8L 8cyl 4A)
For this very basic LS, I bought 18" Michelin Pilots (truck came with 16" Goodyears, I believe)- truck now gets average of 20 mpg. I put in many miles per annum - don't just accept the "myth" of poor mileage! Also, the smoother-riding, after-market tires enable my elderly parents to enjoy traveling in this high-riding limo.
Nearly everything. Would highly recommend to anyone. Also, lots of head room and interior space enable one to haul around a whole lot of stuff.
Speakers for the basic models! They are far too wimpy for the cavernous interior! I had the exact same speakers in my 2002 Impala (of course, they sound great in a sedan).