Some say the sail panel issue is every year from 1999-2002 "1998 was not supposed to be effected" but I personally *knock on wood* have never had the issue and I have owned quite a few camaro's and TA's over the past 10 years...so it is hit or miss based on my personal experience. Try to keep it out of direct sun light when possible because that can obviously make it pop its head up.
I would be more worried about the fuel lines than anything else when it comes to sitting for an extended period of time but thats just me...fuel will eventually start turning into a gel like substance if it sits long enough and 8 years in my opinion is more than enough to start gumming up lines and injectors. BUT if they have been starting the car over the years then it will keep stuff moving around and prevent that from happening.
If you are ok with the sail panel paint bubbles then go for it...my current car sat for over 2 years when I bought it because the only previous owner was in the military and was over seas for years at a time and I was perfectly fine with that. I knew I would just fix it if something went wrong.
Just for clarification, when you say the car has been sitting for 8 years has it literally been sitting not being started or have they been starting it once a month or something like that?