Well, of course the best thing to do is to get it professionally tuned on a RR. I'd never even think about messing around with any screws on a car that has been set up properly.

But my car is a bit of a shed. And it's some kind of miracle that the engine is running at all. After I bought it it had no compression, due to jammed piston rings. And I think somebody has fiddled around with the metering unit before.

So I just take the risk and try to set up the car as good as possible as I simply don't have an opportunity to get is set up professionally.

And well, a blown engine or a melted piston isn't the end of the world...