ARC8 is lighter than EC7, but EC7 is suppose to be a little stronger. They look better too , IMO, but they large opening on the ARC8 is to make it easy to change out the wheels. It definitely works since you can get to the bolts VERY easily without worrying about scratching the wheels.
If you're going to consider the TE37-SL, but why not includ the regular TE37? They're suppose to be a true forged wheel, where the SL' don't seem to be.
Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."