I have 26000 km on my plus four . I find the suspension very confortable and enough for a normal driving style . I have to be carefull when passing over a speed bump. I have made a drifting course with an racing pilot as instructor . He doesnt complained about the suspension. I dont think that adding more options will increase the value of the car to be sold or not . The regular customer doesnt look at that.
I had avo rutherford and a sport exhaust on my 4/4 sport . She was sold the same price as without but the cost of the sport exhaust was 2500 euros .A plus four from 2020 could be sold 85000 , 90000 euros in Belgium , a new plus four is 120000 euros . For the price difference you could tune as you like a 2020 plus four and it will be less expensive than buying a new one.