2.5" o2 housing with 3" downpipe or 3" all the way ?

[ShadeTreeDSM]

right now i have a downpipe off of my 1g fwd , its 3" all the way, it has 3 bolts holding into the back of the turbo and theyre pain in the ass to thread in because i can only use a shorty 12mm wrench. Also it hangs to low under the car and i when i "bottom out" it scrapes & loosens the bolts on the turbo. so im getting a new downpipe made.

so i was looking on punishment racing & saw this. looks like a good idea.

2.5" o2 housing

http://www.punishment-racing.com/comingsoon.html

3" downpipe

http://www.punishment-racing.com/meganracingdownpipes.html

im currently running a 57trim & pretty much plan on staying that way, when i dyno it in a few weeks im only looking to put down 400 to the wheels .

so is 2.5" -3" alright ?

or do 3" all the way ? ?

 

[2gGSX]

2.5-->3" should be fine.