Just got back from a little cruise, a little cooler temps here today at about 70* my engine temp did not go over 190* usually stayed about 180, which is great, trans temp stayed at 150. Can't believe how those couple changes we did lowered the temp. My mechanic was quite surprised as well. He didn't think it would make that big of a change.
I will look at boost to see if increase next time I drive it and can get on it. I have a 2.49 pulley and is normally about 9lbs.
I use Valvoline 5-30 full synthetic, it's what it came with from Roush. I've been a faithful Valvoline user for 50+ years, never had an engine parts issue ever and vehicles with over 300,000 miles, so I'm hesitant to try anything else. I try to always use Fram filters. I am however considering switching to waterless coolant.
I don't have a catch can, could never find one to fit my car, nobody makes one for the 2010 with a M90. I 've got 50,000+ miles and never had an issue without it. Puffs out a little cloud of blue smoke once and a while when I start it, but it's never fouled my plugs or anything. Don't have any of the issues you described. At this point don't know why I'd need one.
If I need to boost my octane, say for a track day, I add this to get me between 93-95 ocatane.
http://race-gas.com/
IF you ever remove the M90 from the roush aluminum manifold, you will see oil from one end to the other. Dimora posted all the pix, when he swapped his M90 to a Roush TVS-2300. You get the same thing with a TVS-2300 too. The only fix was the catch can. I used a JLT but any brand catch can will work on the 2010. Output hose on catch can goes to blower elbow on the M90. One of the fellows on the roush forum used a Fram filter on his new ( blown) roush 2012. Filter clogged itself one day, with some internal fram filter defect, then no oil could circulate through the eng....and the Fram filter did not go into bypass mode either. With no oil circulation, he lost the eng. Tried a warranty claim, and Ford rejected it outright. The FRPP filter is all we use. 50% heavier than oem , and 60% more media inside. Will withstand a lot of heat, and high pressure, and uses high temp silicone rubber gasket. The FRPP is what's supplied on the GT-500's. Buy em in 6 packs.
Don't mess with waterless coolant, like Evans. It's snake oil. It's basicly 100% glycol. Boiling point of 100% glycol is sky high, and even more since it's under 10-15 psi pressure. 100% glycol doesn't extract heat like water does, or a 50-50 mix of water /glycol. Sure it won't boil, but it doesn't extract heat worth a damn. Then you end up with sky high CHT (cyl head temps). Poof, there goes the eng. 3 folks here in town lost engs using waterless coolant. That was 6 years ago, and not mustangs, but bmw /honda / gm.