For what its worth, when I got my low mileage 1750, it was fitted with some modern Michelins, 185/65 /14 from memory. While these drove ok and worked quite well in general terms, the road noise from stiff sidewalls, and heavy steering from flatter broader tread was more than a bit annoying. Raising the pressures substantially helped the steering, but the noise and ride got horrible. It should
not have to be like that.
I ultimately put a set of Michelin XAS 175/14. Well to my surprise they transformed the car into a real pleasure to drive, and certainly with the modern compound really don't give anything away on grip, wet or dry at 'spirited' road speeds. The adhesion limit is so progressive you can be fooled in thinking about your direct blood-line from Jim Clark....
If you really like to enjoy your 105, I suggest it is relatively small money for a lot for pleasurable return.
Life is too short for Bob Jane All-Rounders or Wang-Chung Maxx-Ho's on your 105!