A good loc tht is properly setup will not add any distortion. I have even seen factory head unit in SQ comptitions. Hell many serious competition vetermins don't even both with aftermaket equipment in there daily drivers any more. LOC installs certainly have there success and failures and some cars simply can't be used with them (factory amplified systems are a nightmare). Other then that I have heard and installed several systems withe LOC that came out great with no hint of distortion.