I'm not sure how they do things at the GSP but normal procedures within shipping companies do not include the packages to be ripped open, thrown around, and even driven over... yes one parcel I received had tyre marks.    I buy a lot of things through eBay and not once have I had an issue with shipping damage when the seller posts the items themselves.    However if the seller uses the GSP I truly can say that 9 times out of 10 the parcel arrives looking like it's been shipped via the front line in Afghanistan......  

i have been taking photos of parcels for quite a while now and have a nice collection, the most recent attached.

in summary... avoid the GSP at all cost.