Weird... I never had an issue with my fronts wearing down. It was only the rears for me. and I went through two sets of tires for the rear before I even bothered fixing the camber. I installed the camber arms in the rear and although it looks like I should be rubbing, it doesn't happen. I don't see any black marks around my fenders, but I also don't ride with a full car. Most of the time it's only just me in the car, so that might be why. I think my camber is set to -1 in the rear. Before, it was at -2.5 or even more.

 

So you lowered the car on the front only? That's your problem right there.
When lowering a car, the weight is transfered from the suspension onto the tires. The stiff spring rate allows for a lower car and better handling at the cost of dampening. Your tires now acts as a dampenner and takes all the beatings from the road, as your suspension no longer adjust properly to road conditions.
Even if your alignment is perfect, the tire wear will be excessive and uneven. You made the problem even worse by lowering the front only, that may be a factor of many things (excessive front loading, uneven weight distribution, steering/braking etc.) It also doesn't help that our cars weight 3700lbs.
Lower the rear also to reduce your issue, but still expect the tire life to be reduced by 40-50% of its thread wear.

 

Thank you for that. I wondered about it when installing the front springs only, thinking I would come back to do research once installed. Life got busy, I got distracted. The reason I did front only is to get rid of the rev rake. It was an ugly amount of gap on the front. Just over an inch more than the back. So when taking the measurements it was damn near a perfect match to just lower the front with the RSR Downs and level out the car. So I had them installed and the car looked and rode awesome. So, by no means discrediting your response, but if dozens of others have reported the same issue with different types of susp setups, and ride heights, could my problem be something other than the fact that I only lowered the front? I have the rear springs. If it's believed that installing them will solve my issue, I will.

Again. thanks for your perspective.

 

Yes, other members with lowering springs have the same issue, but not as excessive as yours. Their tires last roughly 13-15k miles before seeing inner wear. You're at 9k and your tires are already shot. Lowering the rear will not get rid of tire wear, but it will help balance out the car and reduce the wear. Again, a lowered car will ALWAYS have accelerated tire wear regardless of alignment specs, it's part of the game. Although the IS do seem to be extra sensitive to inner tire wear.
I do expect a set of tires to last 15k-20k on a lowered car, depending on road conditions, driving habits, and tread type, so i'm not surprised many people here are experience tire wear at that stage. I've lowered a few cars in my days, with different spring and countless different tires brands, all very similar results.
I've never lower the front of the car only and left the rear stock, so I can only assume that is the cause of your problem. My suggestion would be to lower the rear along with the camber kit. Then get another full alignment when everything is installed.