what mods do you want to do? lift, lower, repaint, new wheels, new interior, aftermarket stereo, turbo, nitrous....
it's tough to answer your question without knowing which way you want to go.
but if you are after more power, the consensus from people who are way smarter than me on this forum is that the ridge is about at it's max power level for the drive train.
now if you really want to modify, swap in the driveline from the mdx... my 06 mdx feels like it has more power than the 07 ridge on the butt dyno anyways