If you expect to be sitting for any length of time in stop-and-go traffic with the A/C running, you may see your engine temperature climb up into the red. Other than that, there's no mechanical reason not to use it as a daily driver. Other considerations are:
<UL TYPE=SQUARE>
<LI>Security. Will you always have a safe place to park? Can you avoid door dings, etc.?
<LI>Low ground clearance. The Viper has one of the lowest ground clearances of any vehicle. Every driveway is an adventure. This could be a daily annoyance.
<LI>Weather. In Phoenix, I guess you don't have to worry too much about snow (or rain). In other climes which actually experience seasons, there could be a fair amount of days when the weather's lousy and you just wouldn't want to drive it.
<LI>Insurance. If the Viper's your only car, your insurance on it will be considerably higher than if you have a ****** listed as your primary car and the Viper as a recreational driver.
<LI>Depreciation. If you put 12,000 miles per year on the car, it will be worth less than other Vipers of similar Vintage. Not many people are interested in a two-year old Viper with 24,000 miles when there are plenty of garage queens with 3,000-5,000 miles, unless, of course, the price is considerably lower.
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I'm sure several people who use their Vipers as daily drivers will respond. It can be done. If the issues I've listed above aren't a concern, then go ahead and do it. I would highly recommend having a ****** available for those trips into not-so-nice areas or in inclement weather.