I believe people with the HK system are swapping the sub for the fender sub from the mk 7.I have the same question but for the HK system. Will the already existing wire on the boot be enough to exchange the current sub for a stronger spare tire mounted sub or will other mods be required?
Wow. I wouldn't waste my money on that for 2 dB. An SPL meter may reveal a better result thoughI did that swap to fender sub.
Android sound meter and 40hz test tone: 2desibels better
Fair enough. I have to go down the helix route as I don't have the HK systemIt sounds better, and huge quality differences
https://photos.app.goo.gl/VPaZB3WuD8rgP1CPA
If you found a good one from eBay, it is not expensive