just ordered the 6port header, main underdrive pulley, and intake adaptor. intake will probably be the first thing i am gonna put on. any warnings or anything before i start puttin **** on?

 

http://www.mazdatrix.com/faq/pulley.htm

 

does the header bolt up straight on to the stock system, and would it be good if i did bolt it up if the gutted cats had holes in it?

 

The header won't rolt up to the stock converter. You'll need to make a small pipe to go from the header to the converter. Mazdatrix sells converters that have the extra pipe welded to them. Here are some pictures to give you an idea:

You can read the details at http://www.mazdatrix.com/e-gray.htm .