Welcome aboard.
First up those rubber bungs in the console are for the alarm LED (left) and clock adjustment (right). Dinqua's spot on with those initial mods - cheapest way of stopping your pipes going blue and getting the motor doing what it's supposed to be doing, instead of what the environmentalists want it to do.
For better silencers there's lots of choices that are much better than the Triumph ones - I prefer
Staintunes but that's probably coz they're made down-under, like me.
Thunderbike pipes are another good one too.
For bolt on bags you don't mention wether you're looking for soft or hard ones. If it's soft you can either buy bags of your choice with some
easybrackets but that means modifying the bags to suit. You can also get K-Drive bags which come with their own bolt on bracket to which the bags clip & lock.
Brent sells them (and bunches of other custom parts).
While we're talking about luggage for big trips, the
Biker's Friend works well on our bike, and you can find lots of sissbar bags like the
T-bags that work well too. You can even pull a trailer if you want to get really excessive.
I'd be surprised if the Triumph Roadster screen wasn't big enough for you, but if not both
National Cycles and
Memphis Shades sell bigger screens - as ssjones mentioned you can use Suzuki Maurader mounts for them.
Backrests are slim pickings for our bikes if you want aftermarket ones - the OEM ones are well made but expensive.
Corbin make backrests to go on our bikes with their custom seats which many folks here will recommend, or you can buy one of the backrests to suit various HD's that bolt to the rear fender below the pillion seat.
Finally if you're a DIY-er and you want to try some your hand at some custom mods, I've got a
website that details several that I've done.
Hope that lot helps you out...
Matt