Hi Mark
Welcome to the forum!
I have the same bike and 'Wire Plus' for a few years now.
The 'Wire Plus' kit was the only available option when my EHC went bad at the time; now many other easier choices...
What to look out for -- or what went bad on mine:
a) Fork seals and dust O rings -- recalled.
b) Tach circuit board in speedo went bad --cover with plastic baggie when U wash it...
c) clutch cable and internal lever/bearing on right side -- better to get upgrade kit to fix if it breaks.
d) clutch basket rivets all broke -- too many burnouts and fat chicks on back...
e) primary side compensator nut broke loose.
f) kick stand -- recalled
g) handlebar mount rubber (to polyurethane)-- recalled.
h) chirp noise from secondary belt -- Spray with Fuchs Proprep silicone spray and have yet to install new teflon coated pulley.
i) exhaust pipe cracked -- rewelded crack
j) footpeg rubber wears out quick.
k) new battery about every 3 years -- Tomioka or Braille and charge once a month depending how often you ride...
l) primary drain plug leaks.
m) stock air filter is garbage -- most get K&N replacement; or other high end spike.
n) not a fan of the fiberglass fenders -- replaced the rear with 05 metal.
o) front brake reservoir rebuild -- recalled.
Other than that the 2004 is a nice ride!

sincerely...
PS: Mine is a Rolling Thunder frame (vs. Daytec) from that year.
You should find out which frame you have since it does affect some parts...
some of the early models had frame cracks...