Bought this car last month from Robbie (97ramsst)...it's a great car..and very fast. I also have a '71 Dodge Dart with a 440 in it and the GN crushes it in everyway.
Can't answer the question about the LS1 brakes but I can tell u that this thing stops on a dime...a "must have" upgrade imho.
If the weather stays nice I might have it dyno'd tomorrow..will post results.