To those who are complaining that car x is not in this pack:
Simply enough, time and money are some big restraints. I'm certain that T10 made a budget for this pack and tried to get access to as many cars as they could, whether they are production, classic or modern, and race, classic or modern. In the time department, it can take months to scan a car for a game. This is an especially important factor in whether or not the ultra-new Porsches would be in the pack, like the 991 GT3/RSR or Cayman GT4. Sure, I wouldn't mind those cars being in the game, but I'm happy with a 991 Turbo and a Cayman GTS.
As for the older Porsches:
If I remember correctly, Turn 10 usually tries to find a willing owner of the car they intend to be in the game before ordering a copy at the manufacter to keep costs low. There might not have been willing owners of a 993, a 911 Carrera RS, or a 928 that Turn 10 could get ahold of. For the race cars, it's likely to keep costs low. Not very many games have a 917 or 935, and race cars aren't as openly available as production cars.
And for the SUVs:
I think that the SUVs in this pack (the Cayanne and the Macan) deserve just as much of a place as a 918 or 919, or even the cars not in this pack. Forza 6 is known for having a great diversity of cars. If that's not enough, the DLC in the game added to that, although a few were complained about such as the limo and the Aztek. In the same way they were able to conjure twenty Porsches from most eras and bodystyles. The SUVs are no exception.
Then again, they'd be useless online. I was and still am against banning the large vehicles online simply because of the diversity. Sure, they might be tools for "wreckers," but when used correctly they can provide lots of fun and challenge into getting first place.
Ironically, I also see a few people complaining about the lack of a Panamera, which ironically is very close to an SUV, though not exactly an SUV.
TL;DR: Time, money, and taste are why people are complaining. You can't please everyone. There was actually someone on Facebook who wanted an S14 rather than Porsches, by the way.
"...and to avoid a rant the size of Jupiter, I will end my reply here." -VerrucktSchakal