$7k is a ridiculous price.
A full set of energy suspension bushings will set you back a few hundred $, granted they are absolutely not the greatest! I know because I put them on my car this winter but they will absolutely do their job and do it far better than 30 year old, worn and dry-rotted stock bushings.
For the serious people there's most likely far better alternatives out there than Energy Suspension, but they pleased me. Also the rear uppers go in backwards from what their instructions tells you.
Everything on a viper is doable in the garage, all you need help with is getting the stock bushings out which require a hydraulic press but your local shop will help you with that if you bring them all of you suspension parts. It will be labour intensive work, but paying $7k is just a ridiculous amount of money.
But does it ride nice? No suspension noises etc?
Just leave it be until next year, you just bought the car and need to enjoy it so enjoy it. If it feels alright and sounds alright it's no rush. It's to be expected on a 30 year old car but as long as it's stable (safe and predictable) on the road and wont clunk it's OK for now - not great but OK.
IMPORTANT:
Also thorouhly inspect your A-arms for hairline cracks, I'm up to 6 or so cracked A-arms on my Viper and I'm not pleased with how this isn't discussed more.