Hi,
Althoug You can buy a Futaba TM-8 FASST 2.4 GHz transmitter module for your 8U radio You also need an FASST receiver like Futaba R6008HS or similar FASST reciever (unless You want to use for example FrSky 3rd party compatible receivers that are cheaper to buy).
You probably want new battery pack in your 8U transmitter (like Eneloop 8 cell NiMh, 2000 or 2500 mAh), and new receiver battery pack (You can use LiFe reciever battery pack if you want, light and reliabale, they are at 6.6 volt so if used unregulated use only Futaba 4.8-6 volt capable servos then if you use Futaba servos).
All this upgrade will cost rather much.
If You want to stay with Futaba and want a new radio perhaps the 8FG Super is a good alternative for You?
I use Futaba 14MZ myself but if 8FG Super had been on the market when I bought my 14MZ I would have probably got that instead since it is actually a 14 ch radio and can do much of what a 14MZ can do. The slight negative thing about Futaba today is that they lack Telemetry except for 18MZ but here in Europe we can buy Futaba/Robbe F1666 Telemetry box and Futaba 6308 SBT receiver to get telemetry on existing FASST systems. But this solutionis not avaliable in US (at least not yet).
http://www.algonet.se/~boem/Telemetr...1666/F1666.pdf
FASST was Futaba first 2.4 GHz system forhobby RC system (came in 2005) and FHSS came in 2010 as a little cheaper solution but it is still a full rage system. The newer FASSTest system with telemetry built in is only avaliable so far in the Futaba 18MZ radio. I would guess Futaba rather soon will come out with new FASSTest radios in same range as the existing FASST radios today, but when we do not know.
Spektrum DX8 is probably wise to check out also.
JR XG8 also with it's futuristic look.
Then You have Graupner MX-16 Hoot 2.4 GHz 8 ch radio (also avaliable as 10 ch, MX-20), Hitec Aurora 9 to name some more.
I use Futaba for its reability first and second for the features their radios have that I want/need.
/Bo