I agree, just ran out of gas and didn't respond..
The guides are one of my go-to places for 'free flow' !
I call it free, cause you almost cannot mis-shape it, and it always yields airflow.
It is sickening to me, to see how much it is overlooked.
I've got a head in the corner of my shop, that someone did, who did a nice job EVERYWHERE, and left the guide completely untouched!
I was at a buddies shop last month and he had a set exactly the same way! Heh?
There's a set of bare 906s on my local craigslist, listed as 'heavily ported', with totally oem guides.. (forehead slap)