Fzero,
You may contact HENRY01 above. I just finished his about 2 weeks ago and I belive he is pleased with the results (still finding out more stuff ofcourse), but he can give you first hand information (from a customer's point of view) what the SD1Plus-EXP sounds/looks/feels like. There are others on the Solton Club as well. To date, over 30 units have been done (currently working on 3) and climbing!!
Thanks,
AJ