There should be ample space for two car seats, no doubt about that. There are 2 ISO fix on both sides of the backseat.
If the
Forte you are driving has enough space then the Stinger should also offer similar space. It's not going to be like a large SUV or a minivan, but what you gain is the joy of driving, cool styling, and a smile on your face everytime you get in the car - heck, just walking up to my Stinger already put a smile on my face.
If you are in the market looking for a 'real' family car and/or the aim is to get much more space than your
Forte, then something like a Sedona should be a logical choice. But I presume, you aren't looking purely for practicality and space but fun and excitement together with practicality - that's why you look at the Stinger in the first place.
I was in the market for a 'family' car because my wife and I are planning for our first baby - so I wanted to make a 'family man' choice (Cadenza,
Sportage), but couldn't get the Stinger out of my head. Then someone (I think it was my mom) said babies will always fit, by the time they grew large enough for space to matter, it will be time to upgrade to a new car anyway. By that time, you will have no choice but to get a Sedona, for the moment, just enjoy the drive.
By the way, I'm not here trying to sell you a Stinger, just sharing my story.