Edit: If there is a better alternative let me know too. I know there is no difference between the US and the JP Duo but the huge price.
Also, I know this would be really expensive, but I guess modding the US Turbo Duo would drop its collectors condition? So if I'd buy a US Duo and then a JP and get the mods would that be the most "collector" way, but also most expensive way, Lol.
Thanks again guys!
I think you might be overthinking it with your "collector" way stuff.
Buy a DUO R or RX modded. I got mine from Doujindance (ebay seller ID), modded for RGB and region. Works good (not everyone is a fan of his work, but I have had no issues). I think it was around $300 after shipping, maybe $320 (can't recall). Get an Avenue pad 6 for your controller. Play some games! Good recipe for fun.
Also, from what I understand, Caps are the difference between the Turboduo and DUO R and RX. Apparently the caps are prone to fail on the US Duo. I've not witnessed it, but that is what I have heard. Can anyone back me up on this one?