When I first got my R, I was like "I will never mod it!" Well that lasted just a couple months, LOL. My wife still likes to remind me of this statement now after I have I/H/E and coilovers and 3 sets of wheels.
I am too br0ke to not worry about resale value of the car however. I make sure to keep all my stock parts, stored carefully, and also I choose to buy very high quality mods that will hold their value should I choose to return the car to stock and need to get rid of the mods. If I ever decide to sell, all the stock parts will go on and the mods will be sold for hopefully a decent %age of what I paid.