I have seen a 3.5" downpipe but not on a Honda. I have seen a 4" on a Honda. The 3.5" was on a DSM.

Thanks for the compliment. What turbocharger do you have? As soon as my "other" GT3076RLE gets here it's being shipped out to have the compressor cover and turbine housing coated. I will most likely wrap the downpipe and intercooler piping with thermal wrap.