I have a 2000 V6 sedan fully loaded and I absolutely love it!! Like JaniVI was saying the "oomph" you get from the V6 is awesome. I would reccomend the V6 if you wanna spring for it. As far as engine mods there aren't to many that I am aware of as compared to the 4 cylinder. The only thing I could find to increase the horsepower was a supercharger and it only gives a max of 80hp. So the only advice I can give you as far as inspections go is check the timing belt like you said and the alternator if it has been replaced or not. That is really about it. Make sure to that the transmission fluid has been changed too!!
*If anyone knows anything else to tune the V6 with more horsepower like a turbo or what not to crank more than 100 horsies let me know*