There really is no difference between the two apart from packaging details.
I believe it's the gapping. My Yamaha V150 outboard motor requires the BR7HS-10 because the gapping on the plug is .039. My boat motor requires .035 to .039. The BR7HS has a gapping of .026 I believe. I think as long as the gapping of the plug is within range of the requirements of your motor you should be OK.
They both have a .03 gap, but we cannot assure that they are equivalent as they are called for different models. Best thing to do is identify the NGK recommended spark plug by motor. If you need assistance give us a call at 1-800-914-1123.
Is this spark plug a cross reference to Champion QC12PEP?
We don't exactly have a cross reference sheet between the manufacturer's, but that doesn't look like it cross references. The way we can match it up is by giving us the make, model, year of the motor. If you have further questions you can call us at 1-800-914-1123.
Is the BKR6EKU the plug I should use as the replacement for an OEM of BKR6E?
It appears the BKR6E is still an active part number, we just don't have it listed. We can only match up the spark plug by knowing your engine application. Contact us at the number at the top of the page for further assistance.
NGK factory sets the gap to a preselected setting, however this may not be the right gap for your particular engine. It is always best to check the gap against the engine manufacturer's specifications.