100k these days is more of a psychological milestone than anything. I don't have a lot of direct experience with Toyotas (Volvo/VW Mastertech) but from what I've seen I wouldn't be too worried. Have you been following the recommended maintenance schedule for the vehicle? Beyond what's recommended in the "severe driving" schedule I say find a competent, trustworthy tech and listen to what he tells you. Avoid cheap "quick lube" stops. Make sure the guy that handles your vehicle is your go to person for everything. Oil changes give a tech the opportunity to scrutinize a vehicle, looking for anything that may be wearing out, broken, leaking, etc. It really is all about being punctual and thorough with your maintenance, and using someone you can trust; preferably a specialist, preferably not the dealer.