Given how we're picking these cars from the UCD, I plan to pick the Toyota Aqua S and then modify it, so that it can take me as far as it's able throughout the campaign. Overall, I wanna buy as few cars as needed, mostly obtaining eligible cars as prizes from the campaign, licenses, and so on. That said, I plan to buy a second Aqua to leave as-stock.
EDIT: I mostly want to pick the Aqua since the other two were already in GT Sport, and I skipped GT6. Not to mention how appropriate it seems, picking a car from the first manufacturer partner.
EDIT2: I mean, that Aqua seems like it'll at least take me through the Sunday Cup, and the Japanese FF Cup. Maybe the Japanese Clubman Cup, too, if I modify it.