... It was the 2nd brake warning message...brake fluid. It looks like there is heaps in there...
This seems to be common in earlier model Soarers (91/92?), top it up until it's slightly above the "FULL" line and give it another go.
About the boost thing, how early and how hard does it hit? I notice in my Soarer that boost comes on (albeit very gently) from anywhere above 2700RPM and from 3500RPM it spools up to full boost and all the way to the redline. Gotta love that 1JZ!