I haven't done the SD1 mod but I have done the MT-2 Sustainiac Tri-mod and the BD-2 H2O Mod. Both greatly improved the sound of the pedals. The MT-2 is pretty useable now (I was going to toss it but decided to try the mod.) I'm still more of a guitar directly to amp guy now but the MT-2 is a lot of fun and very versatile - wide range of OD and distortions.