[bluGill]

A few years ago all the chip your truck billboards I saw were about removing the EGR value for more power, so they for sure were endorsing removing emissions systems. Though this was about diesel engines and I understand the EPA cracked down on those hard a few years ago. Perhaps the only tuners left put some effort into emissions.

[datax2]

Absolutely, in the past some tuning companies had no issue recommending removing emissions equipment, but then standards and laws changed and most if not all companies complied. Banks power is a good example of a diesel tuner who does not advise on removing EGRs.

In the area of emissions management aftermarkets have found symbiosis. Not only has there become aftermarket manufactures of higher performing both in emissions and performance catalytic converters (G-Sport by GESi). But alot of tuners acknowledge that engine performance can be improved with a well catalyzed exhaust system.