Hello I can not see a VX ON forum on the Magnum. I have had enough of new cars packing up and the huge out of warranty bills associated with them. I use to find motoring a pleasure now every time the engine management light comes up on my Astra 2l tdi my heart sinks. I had 100's of thousands of miles, of cheap and simple motoring out of the old side valve and X flow non ecu cars most repairs came under the 3 P's plugs, points and petrol. I have decided to get shot of the Astra and go back in time I have found a Westwinds Panther with the 2,3 Vx magnum lump in it but it need leaded petrol and is present running on un-leaded petrol and plus an additive. does any one know if this engine had hardened valve seats and the owner just changed to unleaded and used the addative as a matter of course instead of adjusting the timing or if the head needed hardened valve seats and was it possible to modify the head?