My wife has an I-Trip which she uses in her Jap car, to be honest its not that great. You tune it to a 'free' station but invaribly it plays up on a long journey, as the frequency is no longer ' free '. Takes a lot of messing around to get an acceptable service..
At least her 'pirate' station is now legal, so cars in the same jam can pick up
Aux-in on my SAAB is a lot better, worth the aggro of fitting if you can.