very tru, but their also more expensive... carsound goes from $120 retail, and random tech i heard is around $280-300. both pass emissions and with limited warranties, and both supply more air than stock, so im going with the carsound. but im really buying this cuz my OEM cat is DEAD, gone... CEL has been on for AGES... and car feels worse, need to replace ASAP. i think im gonna buy the carsound on ebay... buy it NOW $55