98 Royal Star Tour Deluxe Exhaust
I too have a 98 Royal Star Tour Deluxe. Here's the problem - 98 was the first year Yamaha put this bike out, since then they've modified it substantially. In 98 the exhaust is essentially a single piece on each side from the headers all the way back to the tail pipe.
Everyone makes SLIP ON mufflers but three is no way to use them without cutting your stock exhaust up, and no one wants to do that in case it doesn't work. You have essentially two options, that I'm aware of.
1 - go to a salvage yard and buy the system off a wrecked bike, take it to a custom shop and see what they can. This will cost money. I bought my bike brand new Memorial Day in 98 and the exhaust shop wanted $1,000 PLUS a sacraficial system!
2 - BUB used to make a 4into2 system that would fit BUT it isn't listed in their book. I spent 4 hours on the phone with BUB in June of 98 and they finally found a system that felt would work on my bike. They agreed to send it to the dealer and if the dealer said it wouldn't work they agreed to take it back. IT FIT, I was ecstatic! I also had a stage 1 carb kit and a K&N Filter upgrade done. This was the ONLY performance enhancement I have ever found for this bike.
I love the bike, but I wish there were more options for it.
Your other possibility is to look at VMAX exhausts for the same year. The Royal Star for 98 used a de-tuned VMAX power plant - same on the outside, different guts. It probably won't be listed in any of the parts books, but you may find a hungry dealer who's willing to work with you to find something that will work.
good luck