My GTR cost thousands and thousands to keep under warranty...High labour costs, six monthly service intervals, silly post track inspections, extra oil changes due to daring to do more than a few 1 minute laps in a row, high vehicle weight all contributed to this cost and I lose warranty anyway after 3 years.
In my Porsche I happily have an annual service which costs very little, low tyre and brake wear due thanks to 500kg less weight and the option to extend my warranty by ten years for $2k a year. It's a no brainier in my situation.
People have a very valid reason for complaining about servicing costs.