SX/SXi/SXi Pro Stock exhaust cooling

[haromang14]

Ok, does anyone know if i can drill out the stock 1/4" barb fitting on the top of my stock 750sx exhaust to tap it to a 3/8 barb so that i can hook it up to my new 3/8 pisser? I know that i cant drill too far because i think that barb is an exterior water jacket and if i drill too far i might go through the water jacket into the exhaust chamber, is this correct? I noticed that the sxr 800 stock exhaust is like this

 

[haromang14]

Forgot to add these pics to the first post

 

[haromang14]

And i heard if i put a "T" in the hose that comes out of the head that goes to the stock exhaust and just route that to a pisser that it will take more water out of the waterbox and make the ski more peppy, or will doing my first post accomplish this?