Just about everyone is using isolators- they come on the car. Almost everyone reuses them or replaces them unless they want more of a drop wen changing springs, then some people opt to go w/o isolators. That will probably increase noise though.
When I had my 88 GT, I didn't use them and didn't see any difference negative wise. I do believe it sat a tad lower though. Which I thought was a good thing. Just my .02
Mav