A definite improvement. Not that the originals were bad, but its really got a cool growly sound now. They are a little hotter too and provide a much needed volume boost. Just for comparison I measured the DC resistance on the pups: Geddy bridge: 7.47k Geddy neck: 7.27k NJ4 bridge: 8.10k NJ4 neck: 7.95k I also noticed the Geddy has CTS pots and brass plate shielding in the control and Pup cavities. Better quality than I expected. I have a black pickguard coming and that should be the last thing I will change. Love my GLJ!