I have heard that the stock magnum heads are often cracked. The ones I have on my 360 were not, but I may have just been lucky.

As for the crosswinds intake I just spent the extra $ for a USA made Edelbrock Performer RPM AirGap for the Magnum motors. USA made. No extra bolt holes to plug. It is nice that we're still able to buy parts for our cars that are made here, since with other things we rarely have a choice anymore.