You are totally right Zoot in that different brands of tyres can have an effect on ride quality- i have found in my experience that Michelin tyres usually are more comfortable than for example Falken. Best thing to do is read
reviews of the tyres you are considering and they should hopefully
guide you.
It is possible that the potholes are the reason behind the tyre pressure loss, get them pumped up and monitor them because you may have a slow puncture.
The individual mode allows you to adjust throttle response, steering weight and ambient lighting. For example you could have sport throttle response and red ambient lighting with normal steering weight. It doesnt give any extra power in sport but changes how the throttle reacts.
You may find as the car gets older the ride does get more crashy as parts wear but you could either
1. Changes the tyres to a softer compound.
2. Fit new suspension components
This depends on how desperate you are to change the ride and how much you want to spend.