+1 on that 4gasm!!
As for the drilled out exhaust ACE, I drilled my stock exhaust and I liked it too. Much better than the stock sound. But I hadn't heard the holeshot; or any other exhaust on the max for that matter. The Holeshot exhaust sounds lightyears better than the drilled exhaust. The drilled exhaust sounds great at low rpm's and idle. But at higher rpm's it sucks IMO. The Holeshot doesn't loose its snarl at higher rpm's, but still sounds great at low rpm. All my Harley buddy's love the sound. We went thru a couple of tunnels this weekend and the Holeshot is really deep sounding and seems to pressurize the tunnel. You feel it as much as you hear it. It's like having a bass box on the back:biglaugh:. The Harleys don't do that for whatever reason.
Now with that being said my cousin had a 86 vmax about 5 years ago with the Kerker 4-1. I don't remember the tone but I remember the volume. It was loud as sh--! I'm not saying that's bad, but that would seem to me to get old fast on the interstate. The Holeshot exhaust seems to mellow once your at cruising speed but if you give it any throttle at all it comes to life. They are plenty loud for getting looks. They still have the V8 sound:biglaugh:! As for the Kerker I can't give an opinion as I haven't heard them in so long. I know a lot of guys talk really good about it on here.
Hope this helps!
Ride Safe/Arrive Safe!
Shane