http://www.geartaker.com/product/r4-gold-plus-card-for-3ds-dsi-ll-xl-dsl-ds

it took me a while to get it to work but that was my own fault :P i forgot to read the included documentation. i found the official site and downloaded the appropriate firmware (2.10T English, in my case) and copied over my HB and backup games, and a few videos. then put the microSD card into the R4 cartridge, the cart into my ds, and started it up. it takes a bout 5 seconds for it to actually get to the loading screen because i have a slow microSD, but it works AMAZINGLY well. a few games dont run at full speed but thats the SD cards fault, not the R4.

5/5 definitely recommend to all my friends!