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It would be good if Koni listed compressed and extended lengths on their website. How can we figure out what shocks to get if we can't get the specs anywhere? Seems to be the same story for every shock absorber manufacturer.

I wouldn't bother with their website. Call their authorised distributor, they're really helpful. I just need to cut some Commodore springs for a reference height, see what I think of the spring rate, get some customs made and then order some short stroke rear shocks...

Just another little update for reference here, I bought some lowered springs from Eyecon, they're a reasonable amount tougher than stock and lower too (maybe 20mm vertical tyre to guard gap), to keep these captive, the rear shock's maximum extension must be no more than 500mm. 480mm would be better though, to keep the springs firmly seated. This is still plenty of extension. Obviously shock lengths will vary for different springrates, and it's worth noting that these appear to be fixed rate springs, not progressive, but it's a starting point at least. That's measured, very crudely, to where the shock rubber joins the body of the car.

I'll try and contact the Koni distributor I dealt with ages back and see what would suit. Mounting points are the same as VR Commodore wagon I believe, but lengths will be different.

How long are the stock ones? I thought they were about 490?

I found that Falcon XE-AU shocks are slightly shorter than Commodore ones. Koni make reds in standard length and short length, but I don't know what lengths they are.
The lower bush is different though, would need to push out the tube.

Found some other brand on Ebay which lists the standard one as 487mm extended and 440mm for the lowered ones.
Standard - http://www.ebay.com.au/itm/Rear-HD-Gas- ... 1c1bd29207

Lowered - http://www.ebay.com.au/itm/130644119484 ... 1423.l2649

Ahh yes, that's handy to know! My current rear shocks would be about 520mm I'd say. They're NOT factory though, someone's put them in there at some stage and they're not amazing. Fine for driving to the shops, disappointing for anything fun. Having said that, my measurements were pretty vague, as they were still fitted to the car and I was pretty much doing yoga to measure them (oh, and the measuring tape's curly). Having said that, I reckon I'll order some Koni's around the 460-480 mark, just in case I choose to go lower at any stage. I doubt I'll go any tougher, especially not on springrates - I might even go softer or progressive springs, and use the shocks to stiffen it up to improve ride quality for the lighter rear end.

There are some Koni Classic shocks selling on ebay right now if that helps. Not sure of rod length though.

FYI people, the Koni finder lists the following:

Under "GM Australia (Holden)" > "Piazza" > "Piazza YB 04.86-90"
Classic Front, red in colour: 80-2275
Classic Rear, red in colour: 80-2233SP1
Sport Front, colour not listed: 82-1886

However, I've just emailed the primary Australian distributor to ask for something specific for my application, and mentioned a maximum extended length of 480mm, and asked for a slightly tougher range of damping to match the Yellow fronts I'll be putting in. As soon as my yellows arrive (they're second hand, and off of a Gemini), I'll check the part number to see if it matches the "Sport" fronts listed above.

I got Gemini yellows for mine too, they're "82-1886sport", so the same thing as the Piazza one.

Looking at this
http://microimageonline.com/forums/show ... sassembled

Should be able to get the Piazza red rears, pull them apart and make up a longer droop spacer (the white thing).

I checked the length I need on mine to stop the spring falling out, about 440-450mm extended from the base of the top pin to the centre line of the bottom eye.

Interesting.