Yes I did. It
is worth it. As run/brake, it is much brighter than my 16yo trunk bulbs (which I need to change). There are lots of ways to add light to the back, but it just seems to make sense to use the fender knockout on the IS to add a run/brake light.
A lot of guys have gone looking for used tail light assemblies from Shadow ACE, Sabre, and a couple other Hondas, but while the lens is identical, the mount assembly is not. I believe they have been made to fit (with files and hammers) but you are better off to get new parts for a straight bolt up. Parts ran me about $130 (few years ago)
One other thing. I have no CB, but it has been reported the CB mounted under the trunk just slightly interferes with adding the std tail light assembly under the trunk in the IS knockout. I also seem to remember someone writing they were able to make it fit by turning the CB sideways in the mount (or moving the CB a bit to create enough clearance).
This info is some 10+yo, and prices are probably off, but a good starting point.
Honda standard/tourer taillight 33701-MZO-67117
RUBBER boot
80122-MZ0-000 001 $5.67
01 COLLAR
17216-HA7-670 002 $3.40
21 RUBBER washer
80219-KCZ-000 002 $2.50
23 BOLT, FLANGE (5X25)
90112-GG2-900 002 $2.50
Maybe the wiring harnesses for the Tourer.
OR
33701-MZ0-671 tail light assembly $110.65
80122-MZ0-000 rubber $5.67
32102-MZ0-000 wiring sub-assembly $5.52
32103-MZ0-000 wiring sub-assembly $8.86And you can add an led array in place of the 1157 bulb. It is plug and play, but I seem to remember I had to shave a little here and there on the inside of the lens so the array would fit. (Think it is covered in instructions)
http://www.amazon.com/Radiantz-Tail-Light-Honda-Shadow-Valkyrie-VTX/dp/B000TK8LY8/ref=sr_1_fkmr0_1?ie=UTF8&qid=1420396352&sr=8-1-fkmr0&keywords=led+array+valkyrie+tail+light