well from my experiance (mods in sig) i have had alot of luck up against the LS1 engines and multiple years of mustangs. The car has 96XXX miles on it and i havnt had a problem with the opti (knock on wood)... im not sure what horsepower im at with my mods, but on the street i have beaten WS6 T/A's, SS Camaros (yes LS1), older model cobras, new bullit stangs, lightnings, and all GT's... now im going to be getting a 100shot and im sure that it will push me even deeper into the "car market" of racing... but with the miles i have, the motor is still strong, showing no problems.. i love my LT1. Hope this helps with comparing the LT1 on the street vs some other cars...

 

My lt1 is strong. I dont really have many mods to speak of and I beat Mustang GTs all the time.Its a good,durable engine

 

I love my LT1, the engine bay is a little cramped but what do you expect its a sports car with a 350 crammed in it. I have had no problems with my opti (knock knock). i am easily at the 350-400 hp mark without my Nitrous. The car has been good to me and i wouldn't hesitate to by another.The auto does great after a good rebuild and my rear end has held up extremely well on the street.