New tanks are pretty cheap so if you feel the stock one is weak, you can get a Hayes, Dubro, or Sullivan. Just make sure they are rigid wall tanks. You could just wrap your stock one in strapping tape (with the fibers). That's what I did. I would at least get a new stopper like a Sullivan brand or similar quality. They are nice and soft and last a long time.

I would not use a soft mount on these engines.

Joe