Google Drive is Google's file sync app that lets you store all of your files online alongside your Google Docs documents, and keep them synced with all of your devices.
Put the client's submitted scope file on the quote for review.
Your quote approver can review the client's scope beside the draft quote, with the uploaded file attached from the scope form.
See revised quote differences in the deal notes for each account.
See quote changes beside the deal amount your team signed off, with the difference recorded on the deal.