Coming from Saab 9-5 wagon ... eyeing a late model XC70

I just went through this and am happy to share what I learned.
CAUTION: I didn't learn everything.
Know that the V70 name was dropped. The entire 70 series was called XC-70.
First off, the whole "T" thing is based on boost pressure (in the old days) and resulting horsepower (currently), not cylinder count.
The T5 in your year range is for the 2.0l 4 cylinder turbocharged engine.
They are the only ones made in FWD and have an 8 speed transmission.
If you see a 2.0l 4 cyl. with a "T6" on its back, it has a supercharger AND turbocharger. These are rare in my experience.
A "T6" can be the return of the 5 cyl. engine. All of these were turbocharged.
It was upped to 2.5l for those last XC-70's. It lived its heyday as a 2.3l (turbo) and 2.4 (non-turbo).

I don't know how the rest of the "T" designations panned out and, frankly, don't really care.
Do know it isn't as simple as 4=4, 5=5 and 6=6.

I'm on my third V70 with a 2.4l (2,435cc) non-turbocharged engine. They were all FWD so you know where I'm coming from.

Volvo marketed a 6 cylinder engine in both 3.0l and 3.2l versions. To the best of my knowledge, most of the 6 cyl. engines were turbocharged.
However, I did test drive a non-turbo 3.2l with AWD. It was a nice car but made a grinding noise.

The 3.2l has an odd addition on the driver's side; the READ unit. Rear Engine Accessory Drive unit.
It's a heavily designed gearbox which is used to drive accessories off the rear of the engine.
There's a bunch of parts packed into a very limited space. When it debuted in 2008, it was heralded as a shorter engine which allowed the 70 series to have a tighter turning radius.
I never had a problem with the turning radius and the 3.2l was later reported to be merely 1/2" shorter than the 5 cyl. "White engines".
So how much better could the turning radii be on the newer cars?
I know nothing about the 3.0l.

The real kicker comes from the fact that Volvo and other companies selected low resistance piston rings to save on parasitic losses to boost fuel economy.
As a result, the new engines used oil and many owners let their engines run low or dry.
All the worse if any of those days' "10,000 mile oil change interval" stuff was applied.
So right there our task of finding a good used one just got more difficult.

A mechanic at a Volvo dealership told me Volvo was paying to replace pistons in the 4 cyl. engines but it's safe to assume any such warranty is long expired.
He also said the same weak piston rings were used in the resurrected 5 cyl.

So, my thoughts on the late model year XC-70's are centered around despair and disappointment.
I've seen a few online and almost flew to the Midwest to see one but the solar eclipse caused airfares to spike wildly and when next I looked, it was gone.

I hope some of this helps.