Tony Dragon  gurgled happily, sounding much
like they were saying:

> What a very interesting post.
> I am so worried over this, what shall I do, all these decisions to make,
> its just one thing after another.
> 
> OH, I know what I'll do, I'll just carry on as before & wont buy them.

Of course, what Duhg ignores (or, more likely, doesn't understand is that 
there _are_ situations where they will indeed improve performance and 
fuel economy, and quite possibly emissions.

All they are are higher octane fuels. So if a vehicle is set up to take 
advantage of the higher octane, it will run more efficiently on those 
fuels. Whether the economy improvement is sufficient to overcome the 
extra cost is another matter - with my previous car, it was slightly 
cheaper to use the higher octane fuels at a 2-3p/litre price difference. 
Any higher, and it wasn't.

I've not done a check in this car yet, since getting the timing right, 
but there's definitely a performance difference, which will only increase 
when I get the boost adjusted back up to the factory settings - it's 
currently running slightly low as the wastegate actuator springs have 
weakened over the years.

With the 2cvs, I tend to stick to 98 in France, as a car set up right to 
run on 95 over here will pink and run-on badly on 95 over there - odd, 
since they should conform to the same standards. But the price difference 
over there is small enough that it's not an issue. I could retard the 
ignition a little further, but that would harm power, and thereby economy 
and emissions, as more throttle and thus fuel would be required for the 
same road speeds.

But since when did facts impinge on one of Duhg's rants, eh?