I would say build to order. It's less risk for you and it will give your pedals an exclusive vibe.
Can you tell me more about your Metal Zone mod?
And question 2: I have a Danelectro Rock-a-Bey. It's a dual pedal with an echo and an overdrive. The echo is great but the overdrive isn't. It's supposed to sound like a hot tweed and is very similar to the overdrive on my Hot Rod Deluxe amp. Could you modify the overdrive in the Dano pedal? Maybe with an original TI chip that was in the old TS-808.
The Metalzone mod doesn't use clipping diodes, instead it uses cascaded gain stages so it sounds a bit more like a high gain amp (think Boogie). It also removes some of the nasally mids, and I could install a new ultra-bright (any colour) LED too.
I might be able to mod your pedal's overdrive into a TS-808 (or similar), but I'd need to see a schematic first before I gave you the go ahead. I'd like to keep actual business out of this thread though, as it's not in good spirit to do any sort of advertising (direct or inadvertent) outside of the Seconds Out board, this thread is just to see what you guys think, so PM me if you're serious in going about getting mods done.
