For a no-sew/no-cut option, I think this mod works pretty well...here's the link on the now-defunct Kifaru Forums:

http://www.kifaruforums.net/showthrea...er+straps+zippy

As you can see, you'll have to scare up some hardware, but you can get the Marauder to ride pretty well with the HPG harness--the only issue might be if you need to pack to ride high for some reason...the extra hardware adds a few inches to the minimum strap adjustment length.

FWIW, I ran a G1 Marauder/HPG harness combo as my EDC and was quite pleased with how it carried.  I'm thinking of doing the same mod to the minty Marauder I just picked up, but I should mention that you'll probably have to remove the thumb-loops/tabbing loops off the original Kifaru lower shoulder straps to get them through the ladder-lock buckles of the HPG harness.

To be honest, though, if I were you, I'd probably leverage your Kifaru pod; i.e. just throw your Tara w/ harness in it and have it accessible and ready to go without a lot of faffing about...you're not talking about a real weight penalty for the second harness, especially if you're rolling with old-school Kifaru gear. ;)

My version is a 1 inch webbing strap sewn directly to the centre of a 2 inch triglide (same idea as the normal compression straps, just replace the 1 inch oval triglide with a 2 inch version). Am on the shorter side so this allows me to attach the harness a little closer to any of the kifaru packs that use x-Ray shoulder straps. Currently running the HPG harness on the zippy and tarryall.