Does your opinion change if you look, say, over 5-10 years and think about one car to serve for that time? You might not be using the S3 much at the moment, but if you think of it as a longer term purchase then perhaps that makes a difference in your situation.
Many people view cars as a monthly cost or over the short term, but don't add it up over the years. Selling your S3 now, being free of re-payments for a time but then getting back into another car down the line could be more expensive than just keeping and paying-off the current car. I wonder whether you've paid a large deposit if you owe £32k (list price was presumably closer to £40k)?
I do a fairly low annual mileage across both my vehicles and it's pretty easy for me to talk myself into not spending a lot on these as a result... but it starts to make a lot more sense if I am sure about my needs and stick with my purchase for the longer term - something bought new (or newish) as a keeper and paid off quickly so that it's wholly mine. I've done this over the last 5 years or so with my bikes and a van and I'm getting really good value from things this way. That's what I'm planning with my next car, too.
Unfortunately for me - with my limited miles, on-street parking and family commitments - another S3 or performance car doesn't make sense... but a well-chosen new car should last me many years and work out well compared to changing second-hand cars more regularly. Maybe your current S3 is that car for you?
