Does it sound like it's coming from right behind the dash/firewall where the cubby storage thing is? I had a sort of squeak anytime I went to accelerate from a stop, and was worse when it was cold out. Turns out it was the pitch-stop mount, an easy $30 fix.
I had a similar squeak on my S-Turbo, the garage identified it as a rattling cat. Of course it wasn't, I found the cause myself. I crawled under the car one day and shook the exhaust and traced the squeak to the weld which joins the (gearbox?) hanger bracket onto the down pipe. It's hidden underneath the heat shield but there was just a small enough gap in it that I could see the exhaust rubbing against the bracket. Got it spot welded back up for a fiver and no more squeak.