Any suggestions as to what exhaust tips i can use first while waiting for more muffler choices ?

The exhaust cutout on the 3IS 350 seems a bit more oblong as compared to the round cutout of the 2IS. Thinking I could go for magnaflow

35177




or 35175



do our stock exhausts on the IS350 utilize a 2.25" inlet or a 2.5" ?

 

I think OEM tips look just fine but if you're swapping the muffler 35177 is more stock look. I used to have huge tips on my 2IS but overtime it just looks too big and ricey.

 

The stock tips look better than the ones you posted.

 

If you are going to make a change, get the oblong one since the first one is similar-looking to stock.