Unfortunately, it was recently confirmed that the "REAL" PENNZOIL NISMO GT-R '99 no longer exists.
It became clear that the one turned into Castrol NISMO GT-R in 2000... and CRASHED during free session of Race 1.
As a substitute, CALSONIC SKYLINE '99 was repainted into Castrol NISMO GT-R for the race. The one was used as NISMO GT-R in Suzuka 1000km, and later repainted in PENNZOIL livery.
So the "PENNZOIL NISMO GT-R '99" which we now see was originally CALSONIC SKYLINE '99.
Now it has different parts compared to the real '99 models. (At least the headlights, hood and the color of door mirrors)
I think much like the current Gr.2 cars in GT Sport, we'll only get (and realistically need) a single JGTC-era Skyline GT-R R34. I'd say the same of the other two major JGTC GT500 racers, namely the Toyota Supra A80 and Honda NSX (first-gen, pre-facelift).
What I do wonder, however, is where these cars will fit in? You'd think those older JGTC cars would fit into Gr.2, and they still could end up there, but they also raced alongside GT1-spec racers like the McLaren F1 GTR, which we've already seen put into Gr.3. Granted, said GT1 racers weren't known for doing well against the GT500 racers, but still. Personally, I'd just put the JGTC GT500 racers into Gr.2. But I'd be extremely surprised if the GT300 cars - both from JGTC and Super GT - didn't make it into Gr.3, as in real life, GT300 racers race alongside FIA GT3 cars all the time.
On that front, I'd bring back the Autobacs
Garaiya (both the race car and the
road car), the Subaru
BRZ, and the
2008 Impreza, but also see if other GT300 automakers could be added. It does seem likely we'll get a GT300-spec Toyota Prius, so I suppose that leaves representation from Honda and Nissan, and the former could have the CR-Z. The latter could use the C-West Razo Silvia. All this being said, I'd be willing to omit the 2008 Impreza and just have the BRZ as far as Subaru GT300 racers go, especially since we already have the newer WRX STI as a made-for-game Gr.3 car that has a striking resemblance to a GT300-styled car. I wouldn't even mind that Nissan Silvia being omitted, as well, as there are still other Gr.3 cars that could be good for Nissan, like the Skyline GT-R (R33) LM - a contemporary of the '95 McLaren F1 GTR - which could also be added alongside the rare Road Going Version.
Honestly, the only GT300 cars I'd want back from a prior GT game the most would be that 2012 BRZ and the '08 Garaiya. There's also potential to expand the GT500 cars, too, like with the Honda HSV-010, or the new Supra A90. That's before we get into expanding Gr.2 as a whole, like with modern DTM cars from Aston Martin, BMW, Mercedes-Benz, and Audi.