I compared my StarQuad, SPC, and stock KSC75s, and my very condensed opinions:
StarQuad: Bassier, fun to listen to (had me toe-tappin along)
SPC: Brighter, more detailed, I noticed a few things I didn't with the other two
Stock: Fairly neutral
That was listening to 2-3 songs, and swapping ear clips so I'd always use the same ones.
Afterwards, I did some very quick A/Bing, and frankly they all sounded exactly the same.
Where are you getting the new pads from? I might consider picking up a pair, just so I have 3 sets of non-modded pads.