light flickering/dimming?

[Overdrive]

Hello, I've recently purchased a 1997 Boxster a little past 40,000 miles. I've noticed a bit of an electrical problem, so it would seem. Hopefully I'm posting this in the right area. If not I'll be happy to move it to the right area.

Now, granted, I understand the car is 13 years old, and it did sit for a few years in the lot of the dealer I got it from, but I noticed that the radio very briefly cuts out at random while driving. The sound will cut out for a split second and come right back, sometimes a few times in succession, other times once every few minutes. I also noticed while driving at night that the headlights and dash lights seem to flicker and dim while the car is running. I haven't noticed a change in the car's idle to correspond with the dimming and flickering, and I gave the battery terminal connectors a good shake and tug to make sure they're snug, and they are. Could I be looking at a bad ground somewhere? If anyone can let me know what areas I should look into or components to check, ground locations and such, any help would be appreciated. Thanks for you time.