A nice write-up to read for anyone considering getting rid of that weak stock bypass valve and who doesn't want a atmospherically vented Blow Off Valve(BOV) Enjoy!
http://wwwrsphysse.anu.edu.au/~amh110/Technical_pages/blow_off_valve.htm
http://wwwrsphysse.anu.edu.au/~amh110/Technical_pages/blow_off_valve.htm