I also wonder if the turbo is bit more refined in T5. At no time did I find xc60 t5 to be harsh under hard acceleration (perhaps the tyre noise was drowning out the engine
), but with t6 and t8 which is the same engine people comment (no first hand knowledge) that they sound raspy and unpleasant under hard acceleration so t5 might just be the refinement pick.
I find it difficult to reconcile t6 cost being not that far off t8 too. With t5 being cheaper than D5 and if it gives adequate power it may just be the best choice unless you tow or are a high mileage motorway user. I guess t8 gives that extra bulk that potentially reduces road noise and makes it a bit more stable but at the same time it leans more in the corners, has worse AWD and snatchy hybrid breaks plus it will have longer breaking distance so not sure it’s a clear top choice for refinement any more.