This looks like a Group A or Group 2 touring car used in circuit racing in either the ETCC or BTCC and not a group A rally car. Chris Snowden racing preps and restores these https://alfettagtv6.co.uk/
The group A rally cars actually looked pretty close to stock. I looked at a Group A rally car a couple of years ago in Melbourne Australia, and it is even currently for sale with better pictures than I took of it originally. It can be viewed here - https://classiccars.com/listings/view/1026076/1982-alfa-romeo-gtv-for-sale-in-carlton-vic-3053
Alfa was successful in both touring car racing and rally racing. The rally racing was overshadowed by the Group B racers of this time. In touring car they were very successful taking several championships.
I would really have to dive into this car to see the documentation. It is being pitched as a rally car but set up as a touring car, there were only around half a dozen GTV6 touring cars set up by Autodelta to run, but Autodelta sold a lot of parts to privateers and some of these priveteers were very successful. There are also a few items that have me scratching my head, the blue hose and cone on the air intake is not correct, the dash doesn't look horrible but it doesn't look like the few true Autodelta cars I have seen. and the right shock tower looks like it was welded by someone new to a MIG. The shock towers need reinforcing and this is a high rust area for gtv6's, but Autodelta's standard of work is better than this. Also the few factory built carsthat I have seen used split rim 5 lug wheels, but some of the privateers used the central lug. I would have to really dig into the documentation to have proof on the car as the difference between a true Autodelta built car and a privateer car built with Autodelta parts can be 6 figures.
Kevin