Opinion on the: — proposal for a Council Directive amending Directive 83/181/EEC determining the scope of Article 14 (1) (d) of Directive 77/388/EEC as regards exemption from value added tax on the final importation of certain goods and — proposal for a Council Directive amending Directive 68/297/EEC on the standardization of provisions regarding the duty-free admission of the fuel contained in the fuel tanks of commercial motor vehicles