2554 heat shields and underhood temps.

[JSharp]

Here's another option if you want to fabricate some exhaust parts. Buy the headpipe from an older 2000 series and use one of these with some connectimg pipe to get the muffler where you want it -

Supertrapp USFS Approved Spark Arrestor Mufflers

Lawn Mower Parts and Tractor Parts sells them.