Originally posted by Vapor
I'd like to listen to this noise. Typically if the LMA's are worn, they make the sound at idle. The conditions you are describing point to an OEM exh manifold problem where the welds break internally, causing the inner tubes to rattle at around 2800-3200rpm.
I'd also be very hesitant to use a shorter LMA. Even if you use a spacer, you comprimise the available travel of the lma. If you're gonna be playing around in expensive cylinder heads, expect to pay for expensive parts. ie do it right the first time so you dont have to do it again
I get a rattle at 2800-3000 but its a heatshield.. weird how its only in that rpm range.
good luck