Nissan Qashqai Problems

The CX-5 is the one that gets The Tick. You should only go for diesel for heavy towing or if you drive more than 30,000km a year.

You're right that most people would not feel the difference in grip, more likely in a harsher ride. Lots of dealers would be able to find a Qashqai buyer who wants to swap wheels with a Ti buyer like you.

Low-profile tyres are more vulnerable to damage and generate more road noise. 

The 2.5-litre petrol engine in the CX-5 will give you the zip you want. If you need oomph for towing, go for the diesel.

It's about styling and ultimate grip, aspects that probably don't concern you. Designers save their best work for the larger wheels that come on the higher-priced models, while low-profile generally means better cornering. I'm not generally a fan because of shortcomings in noise and comfort, on SUVs especially.