i just got my new h pipe in the mail today=>> and i opened it up and was looking at it and all and i noticed there are 4 holes in it. im going to guess that 2 are for the O2 sensors but wht r the other 2 for

its a MAC h pipe for a 99-04 v6 stock headers

hte other 2 O2 sensors, you have 4. If you don't have cats, you need to get either MIL's or a tuner to turn off the rears.

no i ordered two pypes hi flow mini cats.

do i need an O2 extention kit to reach the back two holes or should i be fine

where can i get some MILs from?

so i just got the pypes hi flow cats in the mail and turns out they both have another o2 sensor hole in them so that leaves me with 6 holes for O2 sensors. is it ok if i just weld the two holes on the cats shut.

from what i can see by just looking under the car i only have 2 O2 sensors so is it ok if i go ahead and weld both the 2 holes on the cats AND the 2 read holes on the new h pipe

You have 4 02 sensors...

You can just use the first 2 (before the cats), and weld the others up & get MIL's or get them tuned out with an sct tuner.

Or

You can use all 4 (2)before the cats (2)after.

yea i think ill just use the 2 before the cats and the 2 after the cats because i dont see any reason not to. im not getting my tuner till like august so....