Whistling from engine/exhaust between 6 - 7k RPM

[modenaboy]

I've got a 2007 430 coupe 6 speed, couple months old. Around the two hundred mile mark, one of the exhaust brackets cracked, and it was repaired at the dealer. Ran great after that. Now the car is at around 1700 miles, and I notice a whistling (or possibly squeaking) sound at half throttle (or more) between 6 and 7 k. Might be coming from the exhaust, or the engine, hard to tell from inside the car.

Anybody experienced this? Car is running great as far as I can tell, just making this whistling/squeak when I jump on it in that rev range.

Thanks

-- Gordie