Sorry to hear what happened. It sucks to throw cash down the drain, I've been there. It does look very cool though.
Well, muffler sound is sort of like wheel sizes. You get to a point where it gives diminishing returns. Loud will give you drone or an ear ache after awhile. There's really no way around it. Even with $3k Meisterschaft mufflers, you'll get drone. Sort of like very large wheels will eventually give you a bad ride. For sound, you'll have to compromise to get the look. IMO, your options:
1. Keep straight pipe but have muffler shop weld on 'J' pipes to diffuse the drone. It'll still be loud, drone 'may' minimize but there's no guarantee. You may end up throwing more cash down the drain.
2. Pick up a set of Megan M5/M6 for $500 and be done with it.
3. Pick up a set of used OE M5/M6 mufflers and you have the option of changing out the tips to burnt tips. If you can find competition ones, you'll get a much better sound.
With options 2 and 3, the sound will definitely not be as loud and aggressive as what you currently have but there are ways to sort of make it meaner. For M5/M6 mufflers, you can install an exhaustmeister and remotely open the valves during throttle and have it closed at 1500-2k rpm. If that's not loud enough, you can go the route of getting a muffler bypass system and remotely open the bypass valve so it'll sound like your straight pipe when you want. I believe a 650 will require 2 bypass systems.
You can also install x-pipes and downpipes to achieve a more aggressive sound but again, that's more money. Good luck.