I've picked up a set of HAT 6.5s for the fairing and a set of their 5x7s for my lids and according to Hybird Audio both the 6.5s and the 5x7s are 100w rms.
I'm currently running a RF TM400X4ad amp and my question is, is this enough amplifier for these speakers? Should I be running something bigger or maybe adding a second amp?
I'm assuming that you grabbed the I61-2V2 and I69-2V2 speakers and not the mid-bass versions? The TM400X4ad is a great AMP no matter how you look at it. It is capable of pushing all four speakers, but you'll be right at the edge of it's power capacity to drive all four of those speakers at the volume you may be looking for. The HAT speakers are efficient, so you might be fine driving them with 100W per channel. I'd probably defer to someone who is actually running that combination for hands on experience.
But if you want "blow your socks off" volume, you'll really need to consider a second AMP. In my humble opinion you really need 150W per channel or more on the Road Glides for most decently efficient coax and component speaker sets (thinking 91dB or higher).
With the TM400X4ad Amp there isn't much benefit in parallel wiring 4 Ohm speakers to drop the impedance down to 2 Ohms, as the TM400X4ad has the same rated continuous power output regardless of whether driving a 4 Ohm or 2 Ohm load. Looking at the dynamic power output, the Amp does a little bit better at 2 Ohms though.
Ideally, you could bridge the TM400X4ad and run the front or rear pair of speakers, then grab another AMP to drive the other pair of speakers. There's the "blow your socks off" volume you might be looking for.