Hey man sorry about the late reply, been busy.
I used to have a good vid of the twin 2.25 but can't find it.
However,
Heres two vids of the twin 2.25 might help out.
Much better to listen to them on a computer rather than the mobile phone.
my 05 wl holden statesman exhaust tone 2 undercover - YouTube
My 05 WL Holden Statesman Exhaust tone.3gp - YouTube
And this one below Is of the twin 2.5 xforce on idle cold start.
V6 WL Caprice twin 2.5" XFORCE exhaust holden Vz alloytec - YouTube
Like I said earlier the twin 2.25 I had never droned or had the tin sound.
These probably aren't the best to help you make a decision.
I'd recommend jumping on youtube and search up different types of exhausts for the Vz.
Keep in mind thou that exhaust sounds may sound alot different on YouTube rather when your in person hearing them live.
Cheers
Dave.