Do I need to change the suspension bushings on my 914 if it only has 100,000 miles on it, but has been sitting for a few years?

depends on the condition of the bushings, even with the miles and age, they could be "decent", best way to check is to "poke" them with a screwdriver to see if they are brittle or not....if they are still "rubbery" and look okay, then replacement comes down to personal choice...

the intended use of the car also plays a factor, for a daily driver, the rubber bushings are okay, if you "have" to replace them due to damage or you need to get the very most out of your suspension for competitive auto-x or track, the bushing need to be replaced

Originals sag sitting or used

50K miles on these

Replace them!

it's always easy to spend someone elses money

not a cheap or trival job if you have to pay someone to do it

Good example Will!
30 years has a way of effecting rubber parts
Mike, thats whats commanly known as a "Lead"

I know, I'm a terrible salesperson, hahahaha

If you will be driving your car on the street a lot, get the regular rubber ones. The harder bushings make the car a lot less comfortable and they squeak!