There is a thread in the UOA section where "nicrfe1370" posted a speadsheet with 120 Subaru UOA's. I did a bit of rough sorting and found M1 seemed to have higher iron numbers. Of course this is many different engines, climates, driving styles, etc. so the data is not 100% scientific.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1293170&fpart=1
I eliminated the data with less than 20,000 miles (break-in) and OCI less than 4000 miles to get rid of short OCI's. I was left with 90 samples.
I then sorted the data by ppm iron per 1000 miles.
Amsoil, Redline and Royal Purple dominate the top performers and Mobil 1 tends to dominate the bottom end of the list with higher iron ppm per 1000 miles.
I get very similar results for chrome per 1000 miles. Lead, copper and aluminum are more of a mixed bag.
See below for the iron ppm/1000 miles sort:
Miles iron/1000 Oil Brand
13500 0.2 Amsoil S2000
12664 0.3 Amsoil S3000
5786 0.3 Amsoil
4982 0.4 Redline
4323 0.5 Amsoil S3000
6904 0.6 RP Racing 21
22000 0.6 Amsoil S2000
4871 0.6 Redline
7490 0.7 Mobil 1
7156 0.7 Amsoil
5022 0.8 Royal Purple
4983 0.8 Royal Purple
4963 0.8 Redline
7382 0.8 Amsoil
5592 0.9 Tech2000
7777 0.9 RP Racing 21
8800 0.9 Chevron Supreme
7521 0.9 RP Racing 21
5319 0.9 Pennzoil/Pennzoil Plat
5174 1.0 Amsoil ASL
4131 1.0 Redline
5012 1.0 Redline
4950 1.0 Tech2000
5800 1.0 Mobil 1
7579 1.1 Mobil 1
7504 1.1 RP Racing 21
6500 1.1 Amsoil S3000
4632 1.1 Castrol High Mileage
7230 1.1 Amsoil S3000
4407 1.1 Motorcraft
5200 1.2 Amsoil ASL
6840 1.2 Synergyn
7666 1.2 Mobil 1
6790 1.2 Pennzoil Platinum
5089 1.2 Castrol Syntec
5061 1.2 Castrol Syntec
5840 1.2 Pennzoil Platinum
4082 1.2 Castrol GTX
7100 1.3 Castrol Syntec
8332 1.3 Mobil 1, Amsoil S3K
7534 1.3 Mobil 1
5174 1.4 Amsoil S2000
8077 1.4 Amsoil AMO
6540 1.4 Synergyn
5023 1.4 Synergyn
5003 1.4 RP Racing 21
5000 1.4 Mobil 1
7000 1.4 Pennzoil
4888 1.4 Mobil 1
8843 1.5 Amsoil
10000 1.5 Royal Purple
8000 1.5 Schaeffers
5200 1.5 Amsoil ASL
7780 1.5 Mobil Delvac 1
7000 1.6 Mobil 1
4411 1.6 Motorcraft
5000 1.6 Mobil 1
4316 1.6 Mobil 1, Amsoil S3K
13500 1.6 Amsoil ATM
4906 1.6 Castrol GTX
4796 1.7 Mobil 1
4788 1.7 Castrol Syntec
5930 1.7 Castrol Syntec
7000 1.7 Mobil 1
4000 1.8 Mobil 1
6213 1.8 Mobil 1
6165 1.8 Mobil 1
6144 1.8 Castrol Syntec
6000 1.8 Amsoil ATM
7600 1.8 unknown dealer non-synth
7000 1.9 Royal Purple
5921 1.9 Castrol GTX
4284 1.9 Pennzoil blend
6362 1.9 Mobil 1/Amsoil S3K/Mobil 1 T&SUV
7845 1.9 Castrol Syntec (GC)
4046 2.0 Amsoil
6524 2.0 Motul 300V Chrono
5303 2.1 Amsoil S3000
6261 2.2 Mobil 1
9581 2.3 Amsoil S2000
4647 2.6 Mobil 1
6000 2.8 Amsoil
7566 2.9 Mobil 1
7183 2.9 Mobil 1
6470 3.1 Schaeffers
5083 3.1 Castrol Syntec (GC)
7505 3.3 Mobil 1
7433 3.4 Mobil 1
4100 4.1 Schaeffers