Have a look at Progecad Pro 2007. It uses intellicad technology but this release does not seem to have the performance problems of earlier releases. Menus can be an exact copy of autocad or progecads own and comes with extra add-in programs that may be useful. Mechanical version also available...
I have designed and researched for a permeable paving company in the uk. During that time over 500 car parks/service yards were constructed and no freeze/thaw problems were observed (although frost only penetrates 450mm in the UK). We used to run asphalt aisles onto permeable paver parking...
This may be a problem with proxy objects.
I downloaded the object enabler from the autodesk product support website and this cured the crashing problem which occured when trying to open a drawing which had been saved to an earlier release.