I'm getting interceptors for my 2 spots, dont need the AEM for my TC since it's already got a sensor.
depends dude. if you want functionality i would probably go with the interceptor. but if your getting the rpd then i would probably get a pyrometer or egt gauge.
egt gauge and sensor: the sensor gets welded into you're header typically to read your "Exhaust Gas Temperature"
Pyro I think is the same thing.....correct me if I'm wrong.
Yes, a wideband is needed. Unless you don't ever plan on getting tuned. Personally, I'd go with a Autometer Wideband. American Made, you won't need to "port" the A-pillar hole (AEM is larger than your average gauge), and you can get other gauges to match it (ie: other Autometer gauges from the same series, like a Mechanical Boost Gauge and an EGT Gauge).
Yes, they are the same thing. Also a fairly essential tool.
again, the RPD has all of these things and more available on it, I will be getting the RPD.