So I want to grow 2 plants, 1 sativa and 1 indica. Obviously it will have a strong smell, but how strong? On a scale of living in an apartment and others living there being able to smell it, to living in a house and neighbors being able to smell it, how strong is the smell going to be from those 2 plants?
If you rent and are in a situation where they can and will come in at anytime, i,'d advise against it. Not only would they smell it if proper precautions weren't taken, they would likely stumble upon your setup. You likely won't smell 2 plants outside the house though, so if you don't have roommates or if they are cool, then 1-2 plants will be fine. Jm$.02
You can grow with anywhere from 0% to 100% odor control, how far away it can be detected depends on how effective your odor control is. With no odor control you can expect to smell it at your front door and beyond, very risky. One or two plants can be hidden in plain view if you're crafty and have a decent budget.
What Answer said, you can go a step further and use a duct silencer + fan controller to turn it down. The cost of equipment and raw materials is a fraction of what you can produce with a good setup.
The northern lights I did had very little smell and what smell there was was not really skunky, more sweet. But you had to have the tent open or have the plants out to smell it.