I have a 04 Miata MX-5 LS. The mods are K&N cold air intake, OBX header, FM hi-flow midpipe (w/cat) and Racing Beat Power Pulse cat-back exhaust. Timing is advanced to about 14 deg BTDC. The car runs great. Does anyone think it might be necessary to add a wideband O2 sensor for tuning purposes; or will the stock ECU take care of any fuel issues?