Radio DX7 vs DX8 or suggestions

[Hotwheels]

Hello, I am new here to this site so if I posted in wrong are please let me know. I am in the process of revamping my King Hauler. I purchased it used from Craigslist and it was adult owned included trailer and electronics. It did come with just a 2 channel futaba transmitter but has a 4 channel rx. Anyway I purchased a Futaba CAP7 fm radio yesterday which I am returning to local Hobby Town tomorrow. Got home started reading and realized it is 72mhz and I remembered 72mhz is for air only. Other options they have in stock are the DX7 which includes receiver and servos or the DX8 with receiver. Not concerned with servos I am familiar with modifying J plug so they fit Spectrum. I will be adding a sound unit as soon as figure out radio. Also open to other suggestions other than the Tamiya MFC. My hauler already has the now discontinued tractor and trailer light kits installed and working. Also have Novak Rooster speed control in truck. Taking my time with rebuild and want to do it right the first time.
Thanks