Great work bringing this car back. Personally I never knew it existed before for AC. As far as feedback goes I feel it needs to be a lot more compliant over the bumps. I was driving at Silverstone today and was struggling through maggots-becketts complex as it is quite bumpy through there. I don't know enough about suspension settings to get it where it needs to be but I did at least make some adjustments so I could set a reasonable lap time. When compared with the VRC MP4/22 that I also ran today, it's a lot more difficult to drive (yes I know that car has TC but not that relevant in this case I think). I was 8-9 seconds slower in the MP4-13 than the MP4/22 and I think this is mostly because I didn't have any confidence over the bumps. In real life (on the old layout of course) the difference was about 4 seconds.
Hope you, or the original modders, or both can come to some agreement to keep working on this as it's great!