I've been looking into Nav systems for my 07 - and $2500 is a definite ripoff. There are plenty of great systems for about $800. I've been checking out Crutchfield as I've had good luck with them in the past.
I have an 07 V6 with 125K... I've done brakes and scheduled maintenance. Haven't had to replace the water pump. I'd suggest bringing it to a shop you trust and have them look it over.
