I think LED is the current illumination favorite. Which-one, that depends upon if you want the stock headlamp case, or you're willing to replace it.
Marving has an OEM-appearing exhaust which if you go searching for reviews, you may be able to find sound clips to see if it suits your sound parameters.
The Stebel or WOLO copy is a pretty-loud horn, run it with a relay for best effect. It's also compact.
Contact Sean Morley
[email protected] for electrical pieces, and he will have some suggestions on all of these.
Have you read this thread yet?
(52) New Vmax Owner FAQs....new members please read! | Yamaha Star V-Max VMAX Motorcycle Discussion Forum (vmaxforum.net)
Do the 'crimp-fix' to get more power out of the electrical system, and consider going to a MOSFET regulator/rectifier to provide more-even power to charge the battery, and to run your newly-installed accessories.
(52) electrical connectors | Yamaha Star V-Max VMAX Motorcycle Discussion Forum (vmaxforum.net)
(52) Crimp fix done | Yamaha Star V-Max VMAX Motorcycle Discussion Forum (vmaxforum.net) This one is literally-free, and it should be one of the first things you do.
These guys have a lot of bike electrical goodies, like a fusebox for adding any accessories, and relays to make your headlight brighter.
Main (easternbeaver.com)
I suggest you change your brake fluid in both brakes and the hydraulic clutch. Frequent readers know I'm a fan of the reverse-bleed, which effectively purges air from your hydraulics, easily and effectively. I used-to use a Mity-Vac, but I use a 60cc (1cc=1ml) syringe I provide instructions to-fabricate for the purpose, from a visit to your local grocery store and your auto parts store, and perhaps the hardware store, for a total investment of $10.
(52) Clutch slave cylinder replacement | Yamaha Star V-Max VMAX Motorcycle Discussion Forum (vmaxforum.net)