I think this is spot on. My stock 340 does sound very "high pitched" when revved out. Its not your classic beefy V8 noise, it definitely "hardens" up as you up the revs.
I quite like it though, but if you are used to traditional V8s it would sound very different. Maybe I'll get bored one day and do some modding to it.
The HSV X-pipe turns the exhaust into a single system note and takes away the V8 thump because the front pipe lengths are pretty equal from each bank where they join into the X. Like a VN for example where the RH front pipe crosses behind the gearbox and it's longer than the LH engine pipe, the V8 traditional twin system thump remains at lower revs with a single and X-pipe exhaust system.
The crossover or blend area in my X-pipe is 1 7/8" much smaller area than the HSV X and sounds more like an H-pipe system retaining some V8 thump mid range. Top end it's starts to go into the higher pitched V8 Supercar type X-pipe note.
Here's a pretty raw video of the sound, but it's very different to the 340 R8 type note with more traditional V8 thump.
www.youtube.com