the biggest reason people bottom out is because they've got race/sport springs or coilovers on stock shocks, or shocks that are just set too soft. with the right offset, suspension stiffness, you can fit 18's and tuck'em without bottoming out or rubbing. i've seen it done. i've got 17x7.5's on my accord on ground control coilovers, tokico illumina shocks. i've never bottomed out or rubbed...things dropped 2+ inches all around. and i love the way it rides. i dont bounce, or bottom out or any of that other stuff. just remember, the lower you go, the stiffer the shocks need to be to keep things level. i keep my suspension set pretty stiff, but i never was one that liked a car moving a whole lot after a bump or anything. i want to hit the bump, crack in the road, whatever, have the suspension react, and be back to solid as quick as possible. just make sure you take the time to make sure you get the right sizes/offset for the wheels and tires, and if you get coilovers or springs, make sure you get a good adjustable racing shock with it and set them accordingly and you shouldn't have any problems