leaded versus unleaded

[Tim Morgan <timm@torsen.demon.co.uk>]

Dear List,

Having removed the cat from my car some months back due to the fact that
it had completely disintegrated internally I now find myself wondering
whether I can drive my car using 4-star leaded petrol, soon to be phased
out, instead of the super unleaded I regularly use.

Aside from the price difference of around 11pence per litre saving I
will make, is there any benefit to be gained? Or is there a reason why I
can't revert to leaded?

In my old Santana GX5i (Quantum) JS engine, I used to run either 4-star
or super unleaded without any problems...I'm assuming they are very
similar in octane terms, and the basic difference is the lead?

Anyone in a similar position?

Thanks

Tim Morgan

1990 Audi 90qs20v