you can keep the P28 and never mind the cel 22 code. You'd have a 6800 rpm limter instead of 6500 with the PO6.

The PO6 maps and low cam maps on the P28 are damn near Identical.

 

Might have to use the a6 timing belt, unless you can get the tensioners to stretch far enough.

 

And D15B7 mappings are far from ideal for an A6 head/cam.

A6 is the bestest D-series head... if you are willing to run o/s valves and do a little work to one. Not that I'd worry about it when DIY boost controllers are $15 or so.

 

no actually i am using a PM6 ( CRX Si ECU) and im having problems getting the right timing belt for it. Damn it. Actually the block is a JDM D16a (very similar to a z6 block)