i have a v6 and live near Jet and was going to put thier new chip in. Mark at thier shop said it is a quick install $ 319.00 or should i get a flash unit instead?

 

If you get a chip, get one that allows you to store a few different programs in it. You don't want to necessarily get stuck with ONE program.

Flashing is probably the best way unless you heavily mod your car. Essentially you remap your cars stock computer. ONE program but you can always reflash it. If want the best flexability, go with something like
http://www.fox-performance.com/diablo-go.asp
you could always reset it to factory or have a few different programs at your fingertips with the flash programmer.