I think that this forthcoming emission tax is a real bitter pill, of course for people in Marks position where the extra cost means the difference between owing a car he clearly values and all that means (really active knowlegable member of this forum that benefits us all, a strong social element through this forum in owning his omega, sense of pride and achievement in owning and maintaining a classic car).
All of the above are truly worth a lot in these days of overpriced bland tin boxes.
Given the above sentiments there may be a temporary upside albiet not for Mark (although I hope he can reconsider) - you may find more omegas coming on the market which may bring new members - probably people for who the emissions tax will not have such a drastic effect, this may also bring more donor omegas on the market to keep the cherished car market supplied.
I love my motor and while I can afford it I will not change the best when viewed from a 'Bang for Buck' 'Toys for Boys' and sheer 'affordable luxury' car I have ever owned.