Hello dear Abhi
I'm Adrian Oporanu from Romania and I have developed quite a few magento extensions over the last couple of years, as well as overriding core magento features inside my own modules. Among these are a customer review module, an even booking / schedule module, a module where customers can review and rate each other and a module for customers to track the earnings received from selling products on a custom magento site. Among the core module that the buyer asked me to overwrite are the customer module and the sales module.
As for code versioning, I have higher knowledge of git and bitbucket, with svn coming closely behind.
For further references, please check out my portfolio: https://www.freelancer.com/u/adioporanu.html
Looking forward to discussing more in-depth regarding your project.
Regards, Adrian Oporanu.