not on a grp. i thought about that after my reply. going from short tracks indoors in the winter to longer tracks in the summer, the short manifold might be the ticket. i know on some other 5 ports short manifolds are great. I use a dynamite 053 and have a good short manifold im not using that fits good on dynamite pipes...i might have to try that...that sounds killer...right now though im deciding whether to throw my grp in my bag for spare...not looking so good for parts anywhere at the moment?