well 1st and foremost, there are perfectly LEGAL means to electronically (by tune) turn off the afm so it will stay in v8 mode
that can be done with any number of carb legal canned tuners that you can buy either used or from ebay, or new from 4wheel parts or amazon or any number of places
you just have to be sure it is legal for sale in ca, when it comes time to do the smog just be sure to have the carb number from the tune device to provide to whoever is doing the smog they just verify the number int he machine/computer and you are good to go, you do not need to de-tune it or do anything.
if you do it any other way without a carb cerification then you may not pass smog.
other than that I would first concentrate of getting things maintenanced (like the fluids you already did) plus more, like coolant, brake fluid, power steering.
your 2011 DOES NOT HAVE a transmission thermostat, the information you were given was for vehicles 2015 or later
there are some post's on the forum already detailing all the things you may want to address at 145k or can expect to occur in the not too distant future. being you do not know the history there can be some things overdue such as 02 sensors.
wheel hubs typical life is 160k, fuel pump 160k, maf sensor 160k you see where this going.....
plugs n wires should be inspected those should have been changed at 100k like the 02 sensors