Found these engine ringtone on the Lexus Magazine site. They're pretty good - and real. You can listen to them here: lexus.com/performance/#/behind_the_f/sound_gallery/. I like the LFA Engine Start one best because it starts out slow and wouldn't scare me if I heard it in my purse.
The files download as MP3's so if you're a car lover you can get it on your BB. I'm working with Lexus Magazine so that's how I found this site - thought you guys may like it since it's pretty unique (imho).