I was wondering if it is straight forward to fit a 2011-2012 gauge cluster with the 4 gauges in the middle to a 2013 gt base cluster?

 

No idea, but if you're going to go through the trouble wouldn't you rather do a 13+ GT Premium cluster with Track Apps?

 

If you put in a Premium 2011-12 cluster into a base 2013 that is as simple as a swap plus PATS. No other modifications necessary.

A 2013+ Premium requires a new 4-way switch and PATS on a 2013+ mustang.

LEXiiON

 

I prefer the analog gauges rather than the track app screen.

What is pats and how would I get it to display the correct mileage?

 

Passive Anti-Theft System.