I agree with the OP, a lot of mods are just tacky bling, anything that isn't fully reversible actually devalues a machine. Some subtle mods can be quite cool, like adding robby the robot to TZ, but undercab lighting, absurd coloured areas of LED light etc - just shitty.
Still, you can make good money by buying a pin with LEDs for the same price as one without, swapping it back to proper bulbs and selling the LEDs. It's a PITA having to do it of course, unfortunately a few people are starting to do it in this country too.