£70 is cheap, they noramlly go for £100-£120. Should sell rather quickly if it's in good condition.
If you take the spoiler off you'll obviously have the holes in the boot lid, no 3rd brake light (factory spoilerless cars have 3rd brake light in the back window and different parcel shelf), and the boot lid will try and fling itself through the back window when you release it remotely, as the boot springs are different due to the weigth.