The 323's 4WD's existence and rally career is a strange case. It was a car that the Mazda Rally Team didn't really want. The team was based in Belgium, and was the brainchild of German driver Achim Warmbold. They had started out in 1982 with the 'BD' (the first FWD generation) 323 1.5 8V GT, eventually persuading Mazda to homologate a 180bhp turbo version:
The 323 GT turbo ran in Group A for the 1984 season, but the team always had bigger plans.
Over 1983-84 the team had built and run a handful of lightweight 300bhp 2WD FB RX7s in the Group B class alongside the Group A 323 (they got round the need to build the 200 required for homologation by saying it was an evolution of the model previously-homologated by Mazda under the old Group 1/2/4 regulations).
Being only 2WD and naturally-aspirated, it was no match for for the Audis and Peugeots, but it did manage a podium in the 1985 Acropolis Rally. The team had no official manufacturer support up to this point, but now Mazda were interested and the team tried to push for them to produce a 4x4 turbo version of the RX7 for 1986 (with plans to go back to non-turbo for Group S). Unfortunately Mazda didn't want the expense of producing the 200 cars required to be eligible for Group B and had no interest in rallying the RX7, and decided to continue in Group A with a B6T 1.6 16V turbo-engined 4x4 version of the 'BF' 323 (which became the the 323 GTX), which was homologated at the end of 1985, ready for the 1986 season.
Although the new car had excellent handling, the 1.6 engine and small turbo left it underpowered against the Group A opposition - Mazda claimed 250bhp, which should have put them on par with the 2.0 8V Lancia Deltas in 1987, but this seems optimistic given the actual performance difference between them. Reliability was also an issue (particularly gearbox failures) - not unusual for a car in it's first season, but with the initial lack of power it did not bode well for any future bhp increases.
With Group B being cancelled at the end of 1986, Mazda were potentially in a very good position for 1987, with a 4WD Turbo Group A car that already had a season under it's belt, and ex-World Champion Timo Salonen managed to win the second round of the championship in Sweden (a snow rally that is traditionally kind to gearboxes and underpowered cars).
This victory was controversial as it was discovered afterwards that Mazda had been including production numbers of both saloon and hatchback versions of the 323 in it's homologation figures. Unusually the FIA decided not to sanction them and the results stood. However, for the rest of the season showed the problems with reliability hadn't been solved, with the only other notable results being 3 4th places and a 6th. Both works cars were withdrawn on the start line of the first stage of the RAC Rally as it was felt this would be less embarrassing than having the gearboxes fail again.
For the 1988 season, the lack of power was partially addressed by a 300-car 'evolution' run of the standard GTX (called the GT-Ae) with a bigger turbo, but the season was even worse for reliability for the works cars with the highlights being 2nd place at the RAC and in New Zealand, which Lancia did not enter (the winner was a FWD 2.0 Astra GSI) and a pair of 4th places. Mazda did manage to win the Group N driver's championship that year due to privateer teams, but this was mostly due to Lancia promoting their Group N drivers up to Group A to help dominate that championship.
The 1989 season was an improvement, winning again in Sweden and by the next round (Monte Carlo) the weak production-derived gearbox had finally been replaced with an X-Trac 6 speed unit with adjustable centre diff, which helped the team to a 1-2 in New Zealand (again, thanks to the absence of the Lancia team). In Group N privateers helped Mazda win the Manufacturer's championship, but the car had reached the end of it's development however, and a new car with a bigger engine was required.
Mazda launched a new version of the 323 GTX at the end of 1989, based on the new BG 323 and with a turbo'd version of the 1.8 BP engine which produced 280bhp in Group A tune.
However, the car was not ready until over half the season had passed (the 1000 Lakes in August), so the old car had to soldier on until then. The new car's debut was not an auspicious one either, with an 8th place and retirement due to engine failure, so the old cars were sent off to Australia where they finished 5th and 6th. The new cars were entered for the season-ending RAC, but all 3 failed to finish (an accident and 2 engine failures).
Mazda had decided that 1991 would be the last year of works support, and the new car's reliability improved, but it never placed higher than 4th (again, in Sweden). On the plus side, the Group N championship was again won by a privateer in a 323.
The ex-works cars continued in use for a few selected rallies in 1992, backed by the local Mazda importer, but without much success. The cars were still competitive in Group N though, so in 1993 Mazda homologated an improved version, the 323 GTR.
The main change was an update to the engine (from the BPT to BPD) with a new turbo increasing power up to 290bhp, and the front bumper was redesigned to give space to mount a larger intercooler.
In a similar fashion to the previous model, an evolution of 300 GT-Ae models were also homologated featuring some extra improvements for a Group A version of the GTR, However, as there was no longer a works Mazda team, support would be given to privateer teams who wanted to move up to Group A. The most successful of these was the Swedish Q8 Mazda Dealer Team, who managed a 5th in the Swedish round of the 1993 WRC.
By the time the new BH 323 arrived in 1994, there was no longer a turbo or 4WD variant available in the range.
As for the road cars, spare parts are getting very hard to find now. One of it's biggest weaknesses (as highlighted in it's rallying experience) is the gearbox/transfer case (the gearbox on the later BP-engined cars was uprated, but it's still underspec in relation to the capabilities of the engine), and parts to repair them are now no longer available. This has resulted in number of 323 GTX and GTRs being forced off the road, and ending up being scrapped or sold for parts. To get around this, a number of people in the US and Canada have managed to modify the car to fit the Toyota 'Alltrac' transmission from early Celica GT4s and 4WD Camrys,
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As you say they are rare, and I guess getting bits would be an issue?
