How can you tell the difference between a stock GSR header and stock ITR header? Are the main differences the larger piping and smoother bends? Should the header have serial numbers? Have the ITRs header ever been known to rattle like the GSR ones do?

OEM headers bolt up directly to the OEM GSR exhuast without modification right?

Thanks in Advance

 

No, only GSR length headers bolt up to GSR exhaust. Type R, LS, RS, GS, Special edition can be interchanged.