When I was shopping in '00 I thought I wanted a quad cab too, but the prices really jumped up for trucks with those little doors. Ended up with a '96 extended cab because the price was right. Seems like the invention of the quad cab helped to bring down prices on the '94-'97 extended cab trucks at that time. I don't have kids and rarely get in the backseat myself so I don't miss not having the quad option like I thought I would. I have heard the extended cabs are a safer design overall. I must say the 12v has been the most dependable and trouble-free motor I've ever known (my first diesel though). I keep up with all maintenance and have found it to be easy to service without a lot of specialty tools. From what I can tell, the truck you're looking for ('98 12v quad cab) is the most sought after prize of the bunch. I shopped for about 8 weeks and found mine with only 28k miles (4 years old). If you take your time and use every resource available you can still find a really clean, low mile, 12v truck. Good luck.