I havent heard much on the Spectre EMS, so i woulnt know...
As for the greddy ultimate, it's supposed to plug into your cars computer, and control everything that you car can control electronically.
As for me, I have a laptop, and it'll be used for my 5sfte setup, but eventualy when i find an extra flat monitor, i Plan to build a pc into the car. It's what i do... Dont ask...
Myspace.com/d_man85 and look at my pics, you'll see all my computers, Including Frankencomputer, witch i'm typing on now...