Well your alignment problem of the car pulling to the right has nothing to do with your springs. And it doesn't matter what lowering springs you got, you would have the same issues. Your alignment after the install wasn't done right. And it's true that you can get away without a camber kit with the sport drop. I went for 2.5 years on the sport springs without any camber kits. And I got about 25K miles out of my zrated 18" tires which is pretty good for summer performance tires driven somewhat aggressively.
So do you "NEED" a camber kit, no. But it's true that you will get better wear and life out of your tires with a camber kit. I just recently installed a rear camber kit for my car just to extend the life of my new 18" tires.
The shop is gonna say that your camber is off and you need a kit if it's out of spec because they want to cover their butt, you can't blame them. But just because the rear is slightly out of spec doesn't mean it's not liveable.
And it sounds like you were just dropping it for the looks, which is fine. But if you really want to get the most out of your springs, match them with some performance shocks to keep them well dampened, it'll ride better.
Well, just from looking at my car, my right rear tire was totally caving in and my left rear was ok. I asked 4 people whether they thought it was obvious the rear was caving in and all said only the right one, not the left. That happened because I used to go through the speedbumps really fast on my right side (after I lowered it) but not my left and it messed up the camber and alignment. Maybe I had bad installation but I had them installed at California Tint (They've been doing installations for years). After I got the results from taking it to the shop, both told me that my left rear is fine, only slightly off; however my right rear needs to be cambered so I don't think it was an attempt to cover their butt.
Well I guess if you drive it like a grandma over those speedbumps/driveways EVERYTIME and never will hit a curb, you wouldn't need a camber for a while. Because just one big bump, your camber and alignment will be off. I'm saying this through my experience, not out of my a$$.
Yeah and I basically did it for the looks and to get rid of the "floating on a boat" feeling on highways.