Excess Baggage Options

Myself and fiance are relocating to the US on VS12 to BOS this weekend. It looks like we will be taking 8 cases in total between us which means we are looking at 4 x £60/bag (£240) as we are going economy. I assume the tip here is to check-in early to avoid any problems. At least with the US it is per piece as oppose to per kg.
Are there any other cheaper options to consider (e.g. Unaccompanied Baggage Service) instead of taking it with us as excess baggage? I was thinking of negotiating at the check-in desk given our loyalty of using VS over the years!
Thanks!
Are there any other cheaper options to consider (e.g. Unaccompanied Baggage Service) instead of taking it with us as excess baggage? I was thinking of negotiating at the check-in desk given our loyalty of using VS over the years!
Thanks!