You'll only lose 50 hp turing a blower at higher speeds and full boost. 90% of the time you'll lose only a small handful of power to turn the blower. In return you don't have to wait for a turbine to spin up to make power. Yes, a turbo is capable of making more peak power in large part due to this. On the flip side, turbos are typically more difficult to tune and more temperamental for a daily driver. They require turbo timers, boost controllers and things like that. A blower install doesn't need any of this, just the kit. If 8K has you turned off on a Saleen blower, check out the new Kenne Belle lineup. I got mine installed with gages and twice the tune time, rear end lube change and tranny fluid change for right about 8 grand. I really think if you search for a deal, you can have a KB installed for right around $6500.
"Posterity! You will never know how much it cost the present Generation to preserve your Freedom! I hope you will make good use of it. If you do not, I shall repent in Heaven, that I ever took half the Pains to preserve it."