Just posted this info in the UK thread, but thought it might be of some use in here:
The AU Collector's Edition (released by Madman), seems to have a few more extras than the UK.
Specs:- BD25
- 94 mins
- LPCM Audio
- 1.78:1
Special Features:- Commentary with Director Joe Dante & Producer Jon Davison
- Behind the Scenes Footage (SD 9:35 4:3)
- "The Making of Piranha" Featurette with new interviews with Roger Corman, Joe Dante, Dick Miller and Belinda Balaski (HD 19:44 DD)
- Bloopers and Outtakes (4:3 SD 6:48)
- Additional Scenes from the Network Television Version (SD 4:3 12:21 LPCM)
- Radio Spots (1:38)
- TV Spot (SD 0:33 4:3 LPCM)
- Trailers (Piranha with commentary by Producer Jon Davison (SD 2:15 LPCM), Piranha Teaser (SD 0:33 LPCM), Humanoids from the Deep, Up from the Depths, Death Race 2000)
- Poster and Still Gallery
- Phil Tippet's Behind the Scenes Photo Collection
Of particular interest is the 12 minutes of additional scenes from the Network Television Version.