Dead OEM battery. Roof closing mechanism failure on 2014 458 Spider. Sounds like you are handy with the wrench so can do regular oil change/etc. For the most part, the 458 is a robust and durable model but issues necessitating a trip to the dealer do arise on an older/used example. I would write the pros and cons of 458 vs GT3/Turbo S ownership on a sheet of paper and let it marinate for a few days. Just being 9 hours closer to the Porsche dealership would make the ownership experience more pleasant for me but I tend to prepare for worst case scenario. YMMV.
Simple. Conservatively budget for transportation (I would plan for ~3 trips per year), if that amount causes you stress, then don't do it. If not, definitely do it! I also have my car serviced at Lake Forest, and I know they regularly service cars from Iowa, Wisconsin, Indiana, Missouri...the same is true of reputable dealers all around the country. They are used to it, it's just an additional expense and maybe a few extra days without your car. If there's a real problem it could be a hassle, but if you trust your dealer (I do) I wouldn't have any problem discussing and resolving issues over the phone, or worst case drive/fly in for a visit...
I have had my 458 for 3 years and it has only been to the dealer once each year for the annual service.
Weak battery Ticking noise from the dash (the whole front had to be dismantled to fix this) Bad fuel pump, replaced under warranty A coin stuck in the transmission tunnel which made noises when I accelerated and braked hard. Failure of catalytic converter. Strange noise from the passanger side caused by electronic wiring under the seat (this was my previous 458 with the comfort seats). The alcantara surrounding inside the cabin on the a-pillar was loose. The exahust dampers failed so it was constantly open. With this said, I would buy the 458 in a heartbeat if I did not already have one ---> That's how good it makes you feel.