A cartridge with SD card support
You can purchase Everdrive at the official site for 175 USD: Purchase Everdrive 64
I replace all the old main motherboard smd capacitors with high quality solid state capacitors
N64 recap service
UltraHDMI install service form:
This mod its almost impossible to get
The author rarely build units lots and when he do after 20 seconds the website is out of stock
The manufacturer will only build units for large purchases so it worth to him to start a new batch, since he doesn't want to decapitalize by bulding the units
And he either want to take the money from people in advance to do a bulk production
In this forum you can parcitipate on the bulk purchases to get one unit: Bulk purchase.
There is an alternative called N64digital which is a little bit easier to purchase N64digital.