ITRCA

I have a mugen hintake. Just got my SMSP header and the 2.5" exshaust.
Would fuel be to lean on my 1998 itr? Could my stock fuel setup work with it if I reset my ecu? I have a B&M fuel pressure regulator also wich could help.

you won't be lean. Honda's stock ecu is plenty rich. **don't use a fuel pressure regulator unless you have the capability of tuning & measuring the air/fuel - otherwise you're likely to cause a problem with that.