what size mandrel midpipe to get(searched alot)

[civic si hb]

i found a shop that does midpipes here and they do mendral pipes only. the cost is 150.00 installed, non resenated with all parts,labor,flanges,gaskets,ect. i've been searching threw old threads tonight for about 2 hours and can't get a quite soild answer so far. should i get 2.0 or 2.25 piping with a mendral bent midpipe? i want a nice fit and the best possible performance for my car and don't want to do this again. any pro's or cons for both sizes would be very appreciated and thanks for your imput.

p.s. i have a ctr rearsway bar
i don't know if that matters
for fitment puprposes.

[icegrill]

4" should be suffcient. On a serious note 2.25 mandrel or crush bent, will work best for upper rpms.

[SiR_d1]

2 1/4 is the most common size used by most ephatch members

[Surprise]

I thought JSIR went through all this and determined that a 2.25" crush pipe and 2" mandrel pipe is the best for all-around performance. If you have any plans to go FI go with a larger size.