Do it!
Worst case scenario you ruin your edirol, best case is you getting sounding a little clearer. I think what some people fail to realize is that modding gear while won't turn your edirol into an apogee, it is a very valid and good way of getting more fidelity out of consumer, or pro gear.
There are lots of threads about "mods" so maybe that is why some people here aren't as eager to help as maybe threads about other stuff.
But that attitude probably comes from people thinking they CAN get 1000$ performance from a modded 100$ piece of gear. Which delusions aside ain't gonna happen.
Still I modded my M-audio Delta 1010 with some better opamps, and better electrolytic capacitors a couple years ago...no going on 5-6 years now, but compared it to a stock 1010 the other day, and the modded delta preformed better. Enough better to justify the 30+ hours and 300$+ dollars it took me? Maybe not, but it was well worth the learning experience!
So I would recommend replacing the electrolytic capacitors first, because I find cheap electrolytic distortion the most offensive. It "smears" and clouds the sound (again, very general assumptions) while bad opamps, don't seem to sound as bad as bad caps.
Anyway 2 cents worth, and dig a lot yourself, look at other mods, other pieces of equipment, if your lucky you can find someone that has done the mods and can help you out, otherwise maybe not.
Also, make sure the parts are actually crappy before you go replacing stuff. Might just be other limiting factors in the design/signal chain. Usually to increase performance you want to start at what the mic "sees" and then the mic, then the pre-amp, then the A/D...etc..
Anyway you probably know a lot of this stuff, but just want help.
Best,
Abe
Also is it all surface mount stuff?