I just got Two Allums modded boss units. CS3 Opto Plus Mod SD1 GT mod These pedal kick ass. The clarity is incredible, and sound great overall. The GT modded sd1 is great. It reacts so well with your guitars volume knob. very phat tones that can go from warm smooth, to high power gain. Like i said clear, too... The CS3 has so much feeling to it. I have been pulling pinch harmonics outta this thing like crazy! Ive mixed these two with an EP booster (at the end of my chain) and the results are awesome. So much fullnes and thick clarity. Im using a PRS 513 into a Mesa Mark V. All this good stuff, for under $30 (the mod that is). Buy a cheap boss pedal, and have fun soldering, it is well worth it!