I did the mod (thanks Howard for the parts!) and here's what I got:

80M  11W before 13W after
40M  11W             14W
20M  7.8W            11W
17M  4.7W            6.8W
15M  4.0W            5.6W
12M  3.0W            5W
10M  2.5W            4.3W

My test was using the Tune button in WSJT-X, and a dummy load.

I applied the parts the same way the Nigel G4ZAL did, including the tee-pee'd inductor to R86.  This was my first excursion into SMD soldering; I used a headband with a drop-down magnifier and LED light, and seeing the parts was easy.  Actually the whole process was a lot easier than I expected.  

73,
Rowland K4XD