I looked at your profile and it looks like you have a GR? Am I correct? What coilover are you using?
I did my coilover install about nine months ago and it still sits pretty fresh in my mind. I am running the H&R and I remember them being specifically marked for left and right sides. I am currently at about 1.5" drop and have -1.5* camber and have about 1 fingers width between the spring and the tire. This is with both the factory BBS and tire size and the 18x9.5 +38mm and 265/35 tire. At 2" drop the finger distance is about the same. I have had no issues with rubbing the spring or shock body under compression or droop. I am running the stock top hats and factory only camber bolt in the proper hole. Another thing to note is that I have the ALK installed as well and gained some good positive caster, like about 7*. I see that your using two camber bolts and adjustable plates? Why the need for that much adjustment?
I would say as long as you can get clearance between the two, there is no reason to fret. Two fingers is pretty good IMO.
I know the H&R are different than what you are running but in all actuality shouldn't be that different, I would think? Besides spring style/dia. I remember seeing a few threads regarding rubbing when I was researching coilovers, some time ago, mostly on the '07 and down STi's. The only remedy I remember seeing was the use of small spacers, like 3mm or 5mm. I revisited some of that research tonight and still didn't find anything positive, as far as remedies. I believe a brand called ISC may have had a mounting length issue but the OP never reported back.
Basically, there just isn't too much you can screw up when installing these. You bolt the coilover in where it goes and there really is no other way to do it beside caster/camber adjustments.
1. They are installed in the right places/sides? I.E. they weren't marked specifically per side and maybe installed in reverse?
2. You have your camber settings correct. Plates vs. strut bolts. Perhaps dial in more negative camber on the plate and put more positive on the strut bolt.
2.a - Run only the factory camber bolt in the factory hole. Take the other bolt out and replace with the factory noncamber bolt. Utilize those plates for further adjustments.
3. Caster is correct possibly try to dial in more caster? You have an ALK? If not, get an ALK?
4. There may actually be an issue with the mount of the coilover. The bolting flange on the bottom, that bolts to knuckle, may be a hair too short. This is a very good possibility and one I am inclined to believe may be a very good possibility. This would draw the entire shock body towards the wheel. A few millimeters is all it could take to make a fingers width turn into a hairs width, or worse.
5. read the coilover install link below and see if that is how you did it. Just to chiggidy check yoself.
Post up the pics and report. Now you got me obsessing! lol
http://stevetu.com/2009/12/01/09-subaru-sti-cusco-coilover-install/