because there have been lots of people that have blown their motor before 250, the only person I can think of off hand thats using a stock block and is in the 250 range is 505zoom, mine was up there until I spun a bearing but it was because of low oil 
I dont think anyone has blown their motor with the unichip but I would still be cautious of it since its not tuned specific for your car/mods

I dont think anyone has blown their motor with the unichip but I would still be cautious of it since its not tuned specific for your car/mods