Chainsaw Repair

Hi folks
As the heading says, I have an old 038AV in great condition-I've replaced just about everything in the last two years

What, if any, are the successful mods you have done to one of these brutes?
I'm happy with what she does now but I like tinkering with motors so...fire away please

Also, I cut all hardwood here in Australia. Is it a good idea to use a square tooth chain on hardwood? I am good at sharpening and
depth gauge setting so that won't be an issue.

Thanks in advance

Robert