Evening!

I'm trying to get myself a new catalytic converter, as mine appears to have sprung a leak in the braided section somewhere... I have found several options on the web at a reasonable price, but there's a choice for my vehicle.

I drive an A4, 1995 with a 1.9TDi engine 90BHP. But apparently there are two engine types in this 'style'! Any idea how I work out whether I have a -- 1Z AHU -- type, or an -- AAH -- type?! I have my manual somewhere, but don't remember seeing any indication in there before.

If you also have a minute and any experience with fuel treatments, I'm looking to try some kind of a fuel treatment/ engine flush. I've tried the Slick 50 petrol/ diesel treatment which seemed pretty good and perks things up nicely, but has anyone had any better experiences??

Cheers, Simon