Did you try running the 452's in the right sizes to see if made any difference?
It wouldn't make any difference to the grip levels.
They are well known for offering very little grip,hell even Falcon have ditched the 452.
Very surprised that people would run them on a 300bhp rwd car,especially advising them as a tyre for the op to run through winter
i drive quiet competently on them in my car which is 380 bhp V8 and super charged, found them very good in the wet, and manageable in the snow. i drive all year round come rain or snow. not saying they are the best but i think the one thing people don;t take into account with tyres is their right foot. its not an on off switch. if you have a smooth driving style they are more than adequate. in the right width and offset they are fine. much better than the toyo proxies t1r, on a par with the vred sessantas which possibly have the edge.
so many variables on each car. whats good for one is bad for another. the falkens have been a huge improvement over the pirelli assymetricos that were on previously which would twitch at high speed. XKR feels planted now with the falkens.