I wouldn't go any lower than 3.4. And I would go for rockers first. Sounds like your car needs to breath. I bet if you put those rockers on your KR will go away.
Also I had way more KR than you do and i ported my SC and TB and killed my almost 3-6* of KR. Now I have 0* KR just by buying and installing the ported TB and SC from Reptile.
I think I spent 200.00 all together in parts.
You could sell your PLog and DP and go with headers. That would kill your KR probably too and you would set yourself up better for down the road modding and never have to worry about doing anything else to the exhaust side of your engine.
