Specifically appears to be 1749V models for AWX, AVF and BPW engine codes (to start with at least - possibly more in the 110hp range that I haven't identified yet - edited to add - AFN, AVG, AHH) - there are a lot of others that have the 4-cylinder manifold integrated to the casting similar to the BHC / ATL turbos rather than the triangular join which would be trickier unless handy welding aluminium (*) to remove the extra exhaust inlet. As I already have a reconditioned AMF sitting on my kitchen floor I wish I'd had more reading opportunities to start researching this ; might be necessary to get a downpipe / flexi associated with one of these other engine codes with the appropriate flange already in place and get someone who knows exhausts graft it into a A2 set-up in front of the catalytic converter (somewhere by the flexi? - the downpipes for these also have a flexi) so as to avoid having to chop or start welding adaptors onto the turbo casing.
Interestingly, stock images on Ebay of the turbo for the AHH (possibly AHU as well) engine looks to have an exhaust flange that is nigh on identical to that of the AMF / BHC, the seal for which according to 7zap (part 4) - is part number
1H0 253 115 A https://audi.7zap.com/en/rdw/audi+a2/a2/2003-248/2/253-253060/
Going into the volkswagen 7zap set up reveals that there are several different flanges on various different 1.9tdi models. However, there is one I've been able to find so far - with code AGR - that *also* uses the same seal as the AMF / BHC, part number
1H0 253 115 A , suggesting it should mate up. This, along with the AHH & AHU I've seen pictures of are 90hp 1.9tdi with wastegate - and looking the gasket up reveals it was used on a huge range of 75 / 80 & 90hp 1.9tdis since the late 80s in all VAG brands. The obvious question then would be whether the impellor / compressor modules have any more potential in these than those we already have in the AMF / BHC, or whether one of these models could be refitted with the CHRA from a pokier turbo in the same family but benefitting from the direct compatibility of the casting (ie, would the casting need to be machined to fit a more potent CHRA?).
I'm thinking about this too much already....
(*) - just realised that this bit is almost certainly iron of some description judging by how rusty the one off my car was.