As an Amsoil Dealer, I thought I'd throw my five cents in. I'll admit that I'm not sure on the blower question, but I'll talk with some of the gear heads I know and see if they have anything to say. I know Amsoil is working with some of the Monster Trucks out there, and they have massive blowers. But if the engine manufacturer says an oil needs to meet a specific spec, then any oil that meets or exceeds that spec should work. Now how well it protects, holds up to heat, etc, can vary. A synthetic will always outperform a petroleum. And a Group IV or V synthetic, will do better than a Group III synthetic. Most synthetics on the market today are Group III petroleum based oil that the API said can be called a synthetic because of a process called hydrocracking that makes the quality of the oil better than a normal petroleum. A Group IV is a PAO based oil, such as Mobil 1 and Amsoil and what many consider the start of the "true synthetics." Redline, unless they changed, is Ester based and considered a Group V oil. When Amsoil came out and Mobil a few years later both were ester based, but found that esters tend to want to attract and retain water, so they changed to PAO.
The "wives tale" of synthetics leaking past seals I remember hearing back in the 70s was originally a Mobil 1 problem. From what I understand when they first released their synthetic, they were buying an ester from Germany that didn't have any additives to help keep seals pliable, so the oil, in particular their thinner viscocity at the time, did get past the seals. I've heard one story that race tracks didn't want cars running synthetics to use their tracks because this leaking. This has long been fixed.
As for Mobil 1 being put into all these various cars, you left off the Mitsubishi Lancer EVO from the list, however the reason I have heard that they use Mobil, at least originally in the Corvette, is because Mobil gives it to them for free, and in return the they get to put a little plaque that says "Use Mobil 1 Only" on the engine which has brainwashed so many. Their marketing strategy has worked well.
RP I'd place lower on the list of synthetics. They have pushed their name into everything over the years, and are not really that great. I've talked to several racers who used and hated the stuff before switching to Amsoil. I even have some questions as to what their base stock is. Last I heard was that their lower line was a blend and only their racing oil was a full PAO, but then after reading an article in one of the Mustang mags last year, the rep for RP was quoted as saying that all synehtics comes from crude. That is wrong! It does if they are using a Group III petroleum "synthetic" in which case they have moved away from PAOs like most of the major manufacturers. Last year Amsoil paid for testing to be done on their motorcycle oils and compared it to around 20 other major motorcycle oil brands, RP being one of them. RP had about 3x the wear, if i recall the results.
There has been a lot of articles on synthetics in the magazines over the past year or two. Many of them have been pretty good, and some have been so off base, it's scary. I've replied to a few of them to correct some information, one of which was printed in Turbo. The more recent articles I have seen have been better.