if you get a 2000 make sure it had the intercooler recall done. they were leakers on the 99-00. otherwise i love mine drives great. can get 16mpg driving it normal. 9mpg driving like a fool. try to get one that hasent had to many mods like bigger pullys and computer chips. that can take some life out of the motor if it wasent done right. i chip and pulleyed mine and i am knocking on the door of a 12.99 right now threw the 1/4 mile. 2001 and up have lots of improvments like lower gears,bigger mass air meter,aluiminum drive shafts, better programing. they are no good in the snow or ice but thats not what i bought it for. good luck if you drive one you wont sleep until you but one.
I just bought a 2003 model last october, the only problems I've had with it is that the power steering pump was sticking, but a quick trip to the Ford dealer got it fixed... other that that I have no complaints. The 04 models are just carried over form the 03 models, with the exception of a new color... metallic silver i think. I plan to keep mine stock for a while, or atleast until I get back form this next deployment, then I'll do a few things to it to make it a tad bit faster.