Can someone explain what this is to me?

From my understanding i can have vehicle stats displayed on my DX3r/s (depending which i get?) or is only for the DX3s?

What kind of extra equipment is needed for these stats, im sure and extra piece somewhere ...... or many a few extra

The DX3S comes with telemetry (stats monitor) and all that is needed for it. The DX3R does not offer this built in.

Spektrum makes a stand alone telemetry unit also.

does the DX3s also come with the sensors and stuff?

From the looks, its like you tape heat sensor on the motor and such .... where do u get these sensors?

Basically will i need to buy anything extra?

The DX3S comes with temp sensor, RPM sensor.

Nothing else needed, unless you want to set-up onther car obviously. It monitors receiver pack voltage too.

I am buying the R today. I was wondering that also. Will I have to buy a different receiver?

The R does not offer telemetry. The receiver with built in telemetry will not give you the readings on the R; you need the separate unit for it.

Do you know what they run? I have a Nomadio Sensor w/ Telemety now but, Something happend to the radio yesterday and I replaced the batterys with 24 BRAND NEW ( bought them yesterday ) BATTERYS. So now I am with out a radio. Hopefully my LHS has the S then. I love the Telemety. You dont have to check the temp all the time cause its on the screen. RPM AND VOLT!!! Telemety is GREAT!!!

EDIT:
Can I just buy a SR3300T receiver and use the DX3R Radio?

NO! if you want telemetry with the 3R you need to buy the stand alone telemetry system not just the receiver.