[terex26]

my friend has a bone stock 05' 450r and were goin to ride mammoth lakes area in a few weeks, i believe the elevation to be around the 10,000 ft range and im wondering what jetting mods he'll need to do to ensure proper performance while riding at this altitude? oh yeah and he'll have to buy a spark arrestor so lets just assume he buys a t-4 slip on, what jetting with this silencer and altitude?