Workbench 3.0 on amiga?

[psxphill]

Many thanks for your answer :-) then i dont need to change kickstart roms?

If you have enough ram then you can use mkick to soft load a kickstart 3.1 image. It's not going to be legal, but it is possible.
 
Back in the day, I ran kickstart 2.05 and 3.0 on my a500 using a blizzard turbo board that allowed loading images from disk. With no real problems.
 
I switched to mkick when I got a hard drive that didn't work with the blizzard board. I bought a 3.1 upgrade when they became available.

[psxphill]

It is possible run wb 3.1 with kickstart 3.0

You can use the workbench 3.1 disk on kickstart 3.0, but as workbench itself is stored in rom then it won't be much different.