Dear Sir,
I have read your Project description & we worked on Sunshop many years back but if you can provide me URL of the shop, list of customization, we can then give you our precise estimated hours. However, my wise suggestion to you is to get the customization done by Sunshop, as they know their product very well.
Our current bid is just a placeholder since Freelancer requires it but once you respond us, we can then finalize the total cost & payment terms to move forward.
Look forward to hearing from you.
Regards,
YK
LEADconcept