Bade10

I have a "secondary air flow valve" that has seized, apparently its rather common. My auto sparky has quoted me $900 for a new one. Considering this is bloody expensive, and the valve for the other cat is likely to go soon... Im thinking of removing all of the secondary air flow system and flashing the ecu so the codes will no longer show, and to make better output and economy with the 3" full exhaust i have fitted. Has anyone done this and/or knows if it will work? will removing the air system effect the performance? Car is an 08 grb sti hatch (2L) Thanks Heaps!