Best place to buy 3ds flashcart for 7.1.0-15?

AMITYVILLE, Calif. - Jan. 22, 2014 - PRLog -- Today Nintendo 3DS company has updated the 3ds Custom Firmware to V7.1.0-15 with the changes detailed below. It’s mainly intended to improve the 3DS’ stability. just note that you’ll need to update your system before being able to access the eShop. What's more, the support for Nintendo Network ID has been added.
Now you can create a Network ID on the Nintendo 3DS family of systems. This could be a new ID or the same ID that you have created for your Wii U system. And you'll be able to combine the eShop balances and wish lists on both your 3ds and will systems. Keep in mind you'll need the ID to download free content such as game demos.
Be warned, 3ds cartridge users please do not update your system to the latest firmware before you upgrade your 3ds flashcarts. Below is a list of still working 3ds flashcarts with on update patch needed:
-SuperCard DStwo
-R4i Gold 3DS RTS
Personally, I'd recommend buying the r4i gold 3ds rts card, because it is the best 3ds flashcart out there, you will receive the most support. For anyone still looking at this, I bought mine from http://www.r4flashcart.com/8-wood-r4i-gold-3ds-flashcart-... shipping was free and quick, I am really pleased with them.