Power cord upgrade on subwoofer

Did you read the manual carefully first?

Recently I was going to upgrade power cord(I lost the original) for my REL sub, I discovered the manual says 'Only use the power cord supplied'

I contacted the manufacturer why that is, what I need to do with the lost power cord.

I'm still waiting for some answers from REL myself.

I think what I want to make sure is that 'at minimum' what I was trying to do (getting after market PC or using power conditioner, etc) will not degrade the performance or do any real harm.

If I'm assured of that, I can experiment things...