Better to get a used SD1 and mod it yourself. Allums does have authorized mod installers now, but I think they are overpriced.......butthat's because I know how to do the install myself in about an hour.
I had both Allums modded TS9DX and Analogman modded TS9DX side by side. Allums stuff is good, but the Analogman was noticeably better, at least for the sound I wanted from it.
The best price might be if you get used one and send it in for the mod, but Keeley only adds mods to certain pedals, and not others. I know you can send in a Sparkle Drive but I dont know if he accepts SD1's. I think you can send him a BD2 for modding, so I don't know why an SD1 wouldn't be ok. Should say on his web site. I'm waiting for my Sparkle Drive to come back.