The first question is: Will the next "big" update be the one on the 28th with the SF19s, or will that be all that arrives, and we'll have to wait till at least April till the usual many cars+a track formula strikes again?
We've yet to have a singular car* (I know, there's two SFs, but they're only differentiated by engines) teased ahead of time also arrive with other cars (Gr. 3 Supra concept and Audi VGT arrived in the same month but separately). If we stick strictly to patterns, the most we could get is a new track. If thats the case, then I could see either Motegi or Spa. Motegi could be modeled well enough to need minimal touching up for a GTS port, and it'd fit well with the SF19 content. Spa was ***supposedly*** supposed to come sometime in Q1 2019, and this is kind of the last chance to meet that criteria. It could've been pushed back, however. Deep Forest was also confirmed to be in the works, but we have no clue how far along it was. I lean the Spa or Motegi route as far as my prediction goes.
Let's say there's more cars coming with the SFs. There've been highlight or "theme" cars in the past (Group C, two separate SGTs, Kei cars, Hamilton's F1, etc.), and the rest are kind of just a varied selection with no apparent rhyme or reason, maybe now and then they fill a gap or enable a new League event/expansion. The SFs fill that "highlight" role, so any other cars probably won't be very related. I'm still surprised that we don't have a modern Ford GT, 488, 918, or i8, but they don't seem any more likely than they did at the first update, so I can't really say I expect them now. Plus, the updates are predominantly premiums ported from GT5/6.
The last 2-3 updates knocked out a lot of the popular cars that I’d expected since updates started rolling out, but there’s still a lot more. Of the catalogue of GT5/6 premiums that are yet to return, I think these are the most likely:
Alfa Romeo - 8C
BMW - 507
Chevrolet - C5 or C6 Corvette
Chevrolet - ‘69 Camaro
Cizetta - V16T
Ferrari - at this point, almost any one of the past models seem likely. F430, 365, or 250 GT stands out though.
Honda - Civic ‘97
Honda - S2000
Lamborghini - Murcielago
Lancia - Stratos
Lexus - LFA
Light Company - Rocket
Mazda - Autozam
Mercedes - 300SL
Nissan - S15 Silvia
Renault - R8 Gordini
Suzuki - Cappucino
Volkswagen - Scirocco
When it comes to upgraded standard cars, it’s really hard for me to say, PD have thrown us curve balls left and right. I feel like the Delorean, Karmann Ghia, Caterham, C1 Corvette, 2CV, Chaparrals, and maybe now something from TVR’s catalogue could be likely, but I really have no clue. Kind of similar boat with new-to-franchise additions, plenty of curve balls. I don’t think any SEMA winners or the Chris Forsberg would come this month (if there’s more) as it could “distract” from the SFs, maybe April/the following update. I do feel like we could see a new Porsche, though... but like again, no clue which. Basically anything from their catalogue wouldn’t surprise me, save for the tractors.
So for the actual content in the packs? If there is more coming with the SFs, I’m gonna say around 5 cars. If the next full car “pack” ends up being later on, then I’ll say 7.
If March:
Murcielago OR one of the Ferraris
LFA
300SL
Stratos
C5 Corvette
And then if later:
+ ‘97 Civic
+ a Porsche