A new version of the Kadett for the new group was in development at the time, there were at least a few prototypes.
I knew of that, and Opel's involvement in rallying was a long-time one, but I'm not sure whether the Kadett 4x4 could compete with the mid-engined monsters (222R, ECV) or the Group B rockets rebuilt to Group S standards (RS200, 205 T16, Metro 6R4) even if it was well-developed.
As far as the Samara is concerned, I think there was either a Group A or Group B of that at some point in the late 1980s. (After it replaced the fairly long-serving Lada VFTS, a Soviet rally car derived from the typical "Zhiguli" Lada, i.e. the one known as the Lada Riva in the UK at the time.) It's a stretch with the Ladas, sure, as they weren't big in global rallying to begin with.
I agree that the Samara is a stretch, but the Samara S-Proto IMO is a project that Lada might just wanna put some effort into, namely because the biggest problem that Lada's rally cars had was being hugely down on power compared to rivals. The Soviet automakers were pushing hard to improve their offerings both at home and abroad in the 1980s (the road-going Samara was one such example) and the development of the S-Proto as a promotional tool might be beneficial enough for them to go for it.
A conversion of the T16 Group B Peugeot to the Group S standard could be interesting, and is certainly plausible, given that Peugeot's been one of the more stalwart rally-goers among long-established manufacturers.
True, and beyond that the 205 T16 is among the smallest and lightest physically of the Group B cars (along with the Metro 6R4). Peugeot at the time was really pushing for its diesels, so perhaps a turbodiesel 205 Group S might be on the cards....
Toyota's and Lancia's decisions at the time are, as you note, up in the air. A 1990s with Lancia remaining in the major rally business and not quietly pulling out by the end of the first third of the decade would be quite fascinating as a racing ATL. Nowadays, Lancia is seen as a bygone rally competitor and few people associate the surviving brand with motorsports. With a prolonged stay of Lancia in the WRC and many of the smaller championships, we could get a fairly different historical reflection on 1990s rallying.
To be fair, if Group S didn't have a massive cost issue, I can see both Toyota and Lancia staying in it, as the 222R was heavily developed and the ECV was based on the competitive Delta S4, so the possibilities of the automakers staying in there are obvious - but Group S would almost certainly cost more than Group A, which is a problem on two fronts, the first being the cost of competition and the second being the fact that a 20-car production run doesn't make using these cars for the model's promotional purposes a very likely possibility - Lancia cannot promote the Delta with the ECV like they could with the Delta Integrale.
What do you think: What manufacturers that benefitted during the OTL 1990s situation could get into steep competition if Group S was adopted ?
Toyota, yes. Ford, probably. Toyota's gonna go for it in either Group S with the 222R or Group A with the Celica GT-Four, and Ford, having spent bags of money developing the RS200, is not gonna abandon it, particularly since the ideal engine for the RS200 is also going to be used in their Sierra Cosworth touring car which hit the streets hard in 1987. Ford's big curveball could be if they figure out how to use the RS200 drivetrain in the Sierra or Escort for touring car racing, as the Sierra RS500 was known for being incredibly powerful but ratther difficult to drive, particularly against the Holden Commodore, BMW M3 and Nissan Skyline GT-R it ran against in touring car racing.
Lancia, Peugeot, Austin Rover and Audi, maybe. Audi IMO is more likely to bail out owing to their move after Group B into touring cars, as the BMW M3 and Mercedes 190 Cosworth are about to drop into the world of touring car racing. Lancia would have to decide if they could develop a Group S in place of or alongside the Delta Integrale, which was well underway by the time of the end of Group B in mid-1986. They could go the cheaper route with the Delta Integrale, but they might wanna keep the ECV project going to go for the brass ring, but as Toyota and Ford tool up that's gonna be hard to keep up. Peugeot has a big sports car program that will suck up a lot of free cash in the late 1980s and into the 1990s, so I think they may be there for a while with the 205, but once the 205 GTI is out of production they'll probably bail out. Austin Rover is a total crapshoot, couldn't tell you either way.
The losers from Group S would be those makers who jumped into the Group A world in this timeframe, most of all Subaru and Mitsubishi. The Subaru Impreza Turbo and WRX and the Mitsubishi Lancer Evolution became the legends they did on the backs of rallying wins. Subaru might be able to work around this by developing something like the Impreza 22B for the Group S rules, but Mitsubishi is gonna have a problem - their only sports car is the 3000GT, which is far too big to be an effective rally weapon.
Opel and (especially) Lada are wildcards, the former depending on GM's willingness to fund such an effort and the latter on Russia's economic chaos of the 1990s. I'd love to see the Samara S-Proto really go for it - the Russians are not fools, and I'd bet this is the sort of the thing they could be really, really good at.
Thank you.

In alternate history, it's often the little things that are coolest to contemplate. Motorsport AH discussions need a bit more love. Especially (originally) non-American motorsport traditions.
I agree, and as a life-long racing nut, I'm always game to discuss racing AH scenarios and TLs.
