Kunos seems mostly into nimble handlers, which the GTO isn't despite being quite cool. I think some Evo is far more likely.
Well, they can do tuned version if want nimble handlers, the N1 Taikyu PUMA Mitsubishi GTO, "350-390PS" / 1400+kg.
Might be a bit difficult for Kunos to fly halfway around the world to Japan, but yeah Tsukuba would be a nice short test track for AC.
The reason I choose Evo over GTO is, as you said, it's faster, more track oriented and more famous with fans. As opposed to the GTO which is more of a grand tourer. I used to love the 930 HP version in GT1, but now I realize that it's not a very fast car in stock form

It would be interesting to see how the GTO's tech gets simulated though. Maybe Kunos can even go crazy an include the HSR-II 💡
Potential problem with Evo is because you said Kunos only simulates clutch pack LSD, how they are gonna simulate the Evo's AYC system.
If Kunos could do Laguna Seca, they could travel to Japan as well

At least Tsukuba will give a a much needed track diversity, and the Japanese cars could feel at home there.
The GTO when properly tuned IRL is a fast car, it's main weakness is weight, along with weak drivetrain when the power is increased. It's looks cool in Black though, with custom rims, lowered and loud exhaust+BOV, it can do 11s quarter mile with proper tuning.
The Evo AYC is a complex system, there can be up to 3 LSD in a Lancer Evo from I to X ( the package evolve ), front can be open or torsen ( helical/worm ), center is viscous coupling ( normally open, custom VCU torque can be from 50Nm to 200Nm ) or ACD ( wet multiplate clutch bevel gear - clutch pack which can be fully open or lock ), and rear can be either mechanical plate or viscous or AYC / SAYC ( up to 2 / each wheel side AYC clutch pack that can be open to full lock ). The center diff works together with AYC at the rear where applicable ( fitted )
The complexity of simulating the system can be very difficult, the ACD alone for example uses ABS input, steering wheel angle, throttle input, wheel speeds, longitudinal and lateral G's to regulate the locking pressure ( from 0 Bar to 16 Bar ). The Evos fitted with ACD also comes with 3 preset, Tarmac, Gravel and Snow, each with unique programming. Then comes AYC and S-AYC at the rear

Depending on which Evo to simulate, I guess some parts can be simplified or replaced by the clutch pack ( it "works" on the Miata ND which should have torsen )