+1 for improving the exhausts and, to a lesser extent, the air cleaner.
Garage 56 or MMC stage 1 will both let the engine breath better, run smoother and significantly reduce the temperature of the exhaust headers.
The next step would be higher lift camshafts and a mappable ECU to bring it up to Stage 2. Either DIY or dealer fit the Garage 56 kit or Krazy Horse with dyno tuning are the preferred options.
I've had MMC stage 1 for the last couple of years and am booked into Krazy HOrse for the cams and dyno next week
