Question performnace of SSH v1 vs SSH v2

[Amba Giri]

Christopher, thanks for your response.  Our customers have 3.8.1p1 binaries today.  What is the safest and most efficient way to get the v2 performance enhancements to them?  I am not very familiar with the Open Source patch process.  Is there a link for this?
Should I make the changes that I see in the link that you sent  manually to the source files of 3.8.1p1?  Are there any risks/drawbacks to this approach?  Is it better to upgrade the customer to 3.9.1p1 and,if so, does the latter binary have any v2 performance enhancements.

Thank you in advance...
Amba