I've gathered more info on these. Efficientgrips, like I mentioned earlier, are 'fuel saving' tyres. This means the tread rubber is very hard, which reduces rolling resistance, but has the negative effect of dramatically reducing grip.
They are fitted as standard to Seat Exeo TDIs, Vauxhall Insignia CDTIs, Moandeo diesels; and probably similar large saloons like the Passat, Laguna, etc. They are categorically NOT a 'performance' tyre, and should never be fitted to a hot hatch.
