Well

I found this link in the signature of one of the members here..

https://en.wikipedia.org/wiki/Volkswagen_Touareg

It still doesn't tell me which are which....

Or am I just confused because the body styles are Gen 1, Gen 2, and Gen 3 - and there are so many engine and facelift versions???

 

I see posts now about the new T5 chassis. What years do the T4 fit in?

In fact actually for curiousity sake and clarification...

T1 - T2 - T3 - T4 - T5 ???

I've got a 2016 so I believe that's the T3.

That is just local agreed terminology adopted for better understanding. Yours is T4 (Mid 2014 - 2018 ).
Suggest you to visit this site, so you will get an idea:
https://wroom.ru/cars/volkswagen/touareg/history

 

T1 = 2003-2006 (first gen)
T2 = 2007-2010 (facelift T1)
T3 = 2011-2014 (second gen)
T4 = 2015-2018 (facelift T3)
T5 = 2019- (third gen)

 

Look at the chassis designations in my signature too.

The Generation 1 T1 Touareg dates from 2002 and the Generation 3 T5 production started this year, 2018.