And I understand you.
As long as people are aware of the financial implications of borrowing money to buy a depreciating asset and then repeating that process long before the asset has been well used, if not then it does not make financial sense at all and you are just keeping dealers in business and enabling canny folks to buy lightly used immaculate 12-18month old cars.
I will have a wee bet of 1 Scottish pound.........you won't keep your RS3 for the warranty period as by then the next thing will have come along that you feel is worth it - be it the next RS3 or TTRS or whatever
I would rather rag the cr4p out of my warrantied S3 and keep £120*36 (+deposit) for the next one which I would make darn sure is the right one.
I will keep my S3 (which is fine for the way I use it.......not exciting, not a dream car, not looked after but effective) until the warranty is up then start looking about for the next 'take me to the airport car'.
p.s. as per the OP, £16k down the tube in 12months for a 300bhp fast hatch is nuts, you would be better off hiring a select car from AVIS or restoring a 205GTi !!