I have bought 3 vipers, this might help.
I just looked at a 1997 GTS yesterday,
The add was 1997 viper gts, female owned, 8800 miles, perfect, $51,900 with 7/50k ext. warantee.
I called and told her the kbb.com private seller price was 47,800 for outstanding condition car and she said that was the lowest price she would sell for.
When I got ther it was a mess, hood would not open, driver door rubbed and droped when opened, front fascia under beat all to hell, paint had not be taken car and scratches and chips all over, rear rim edge at a curb big time, car ran hot 225 with driving hard, gas cap all corroted, seat ripped and brand new tires.
1) Go to kbb.com and edmunds.com and find out the true market value of your car for trade in, private seller and dealer resell, that way you have a good ball park of true value of the car.
2) Run VIN # Service history at dodge dealer, then call serving dealer and get detailed information on each repair.
3)
www.carfax.com and get car fax lemon report of the car's history, this will tell any accident repairs and such that have been performed.
4)I take a giant magnifying glass with me to look at the paint, it is the only way to see all the chips and scratchs, and OVERSPRAY!!!! especially when they are asking for top dollar. Any imperfections are deductions off the price.
5)Check rims very well. Look for scratches, dings and curb shots on the outer edges.
6)Open and shut both doors and rear deck window. Does the door rub when opening/shutting and drop.
7)Open and close hood, look for gap between hood and front end, should be small. also check to make sure the corners of the hood are hitting the head lights.
8)Check under front fascia, is it all ground down.
9)When hitting the brakes hard, does the front right lock up or squeel.
10) I also open both doors, hood and in each under fender well and look for tape lines and overspray for possible body repair.
11) Get it on the highway and drive it moderately ******* a hot day and see how hot it runs. I drove it in 90 degree's and temp gauge way at 225 and was not even driving hard, so I did not even go on the highway, it was alreadly running to hot for me. might just be low coolant or air pocket, but might be head gasket.
12) Drive it hard, Start off in first nice and slow up to 20 mph and hit it up to 50, slam it into second, if the clutch and motor are solid the tire should spin and chirp pretty good.
I also lauch it out off the hole, semi hard to double check the grip of the clutch and such.
13) Always assume something is wrong with the car and the person is selling it and trying to rip you off, If you see something wrong with the car, ask the owner and if the owner says, OH I DIDNT SEE THAT, OR ISNT THAT NORMAL, then they are usually lying or very retarted.
14) Always offer them less money than what you are willing to pay for the car. If they want to sell the car bad enough they will accept your offer or counter offer im-imbetween the asking price and the price you offered.