Sorry to see Chuckienut deleted. As to IMPROVING the value of the modded piece? NOT. You won't help value and might even crash it. 'Improving' electronics is very subjective. The boys @emo probably spent some time with voicing. At least I hope they did. The more expensive gear, (name your poison) WILL be voiced, sometimes for a 'house sound'. The most popular things to 'upgrade' would be capacitors in the signal path AND the same for resistors. ALL carbon resistors should be changed for some kind of metal film types. Caps are an INcredibble can of worms and I won't touch it with the far end of a fishing pole.
Oh, I just stepped out for a few minutes for a non-alcoholic beer! I'm back now. (Check the dates, old thread!)