No cutting guides off in the ports ..
As per above: NO cutting down guide bosses to the wall.
Picture of LE180 head is pretty much how mine are as well as far as guide boss is concerned
The original porsche T4 914 2.0 head has already an almost ideal ratio intake/exhaust flow from the factory (porsche designed), so not too worry too much.
I run 46/40mm valves fwiw and my heads made 220hp at just 6000 rpm when N/A, so these heads are a very good basis.