Any bikes I've purchased in the past usually already had aftermarket slip-ons installed, and the closest attention I paid to that was a very casual "does it sound good? yep", and on i went with my ride.
I'm now looking at picking up an SV-650 (same as my last bike), but this one is totally stock. These bikes sound immensely better once you ditch the stock pipe, so that'll be the first thing I look to do, but this is the first time I've been in a position to actually choose the pipe myself. My budget for it isn't huge, but any of the sub $400 options should be alright.
So, that being said....what makes a good slip-on? I have no idea what the benefits are of stainless vs. titanium, carbon, etc etc.
I've watched a bunch of youtube videos, and to be honest I think they all sound pretty much the same through people's shitty cameras.
Some of the ones I'm considering:
M4 Standard Slip-on $293
M4 Standard Slip On Exhaust Titanium Midpipes - $366
Two Brothers Racing V.A.L.E. M2 M5 Slip-On Exhaust - $368
LeoVince SBK EVOII Slip-on Aluminum Muffler - $308
Yoshimura RS-3C Stainless/Stainless Slip-On - $379