I have a TT4. It does what it says. I forget if I have the kit one or not, but I also have a little LCD display that I can tinker with. Where there any questions specifically you have about it? I run a Garmin GPS 18x LVC puck with it. I used it with a FT-8800, so I built a 8-pin DIN plug harness to use with it, pigbacked power from the radio itself. You'd have to built a mic & speaker interface for your FT-2900, but it would work fine.
'91 Pickup - Imelda
'08 Tacoma TRD - Donna
'09 Kawasaki KLR650
'12 Gunnar Rockhound 29
"Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security. " --Albert Einstein