Is it worth it buying UHP tires on a low hp car? (155hp)

I have a Ford Focus ST Line (1350kg, 155hp, 235nm, FWD), which I use for daily driving and spirited driving on the mountain roads occasionally. Im about to wear out the stock tires, which are Michelin Primacy 4. The stock tires have 46k on them and it's noticeable the lack of grip when I push the car.

My question is, the times I went spirited driving when the tires had a lot less kms, I found them comfortable and with enough grip to last for sessions ranging from 4 to 6 hours, at around 28 degrees Celsius or more, reaching up to 35.

I know that I will find a difference with any UHP (I was looking at PS4s or the new Pirelli P Zero PZ5), but having only 155hp is making me doubt if its worth the price. It is also true that with my current tires, I cant push the car as much as I would like, I find it a bit understeering on tight corners.