GU ute lift questions.

Hi folks and thanks for taking the time to read and hopefully help me with a few questions I have. I have just bought my first patrol 2011 DX 3 litre and am looking to make a few changes. I bought an ex council service ute and it is running heavier than stock springs (leaf & 9 of in the pack) and I also has a mod plate saying the GMV is 3.9 Ton. Which I assume is more than standard. Anyway the thing I wish to do is raise the suspension by 2 inches and run 285s. Not a big deal right? But I wish to retain the rear springs so I am thinking of getting the rear springs reset and running extension shackles. and then just buying coils for the front and shocks to suit. I figure I will save coin and retain the carrying ability. My questions are, Has anyone gone this way? Were there any traps? Which shackle extensions are best or am I better off making my own? (I am a maintenance fitter)
I have a steel bar and winch so it will be heavy lift up front. any recommendations on spring and shocks. (Am hiding money from wife so this can happen)
While I am at it wheel offset. -22 seems to be a number I keep reading. How far can you push until you run into problems? I have a alloy tray on the back so they wheels wont stick past the guards there but the front might be different.
I am sorry if these a silly questions but I figure it's easier and cheaper to ask a dumb question then do something dumb.
Oh and can anyone tell me what the stock height is and where it is measured?

Thanks
Incy

Good 1 Incy. I have a 2003 gu dx td42 ute. It also has 9 leaf springs. it is very harsh. i was thinking about changing the spring but keeping the height. I thought I could do this by shotening the extra, heay leaves tso they are just spacers an lifting the front to get it level. Hope someonr who knows answers.

Regards

Incy.
I stopped in at Dobinsons the other day and they told me that the spring packs I have, 9 leaf, are 600kg load springs. 6 leaf main pack and 3 leaf secondary. They said standard in 5 and 2. They advised taking 1 primary and 2 secondary out. My thought is to take these out and replace then with a spacer the same thickness on top of the pack and then lift the front to suit.

If you remove the current springs you will loose you GVM upgrade status. Legally but youd probabaly get away with it on a road side inspection.

Assuming you dont need the GVm upgrade id strip it out and set it aside. If you ever want to set up for heavy touring you can put it back in.

Start again. Exetnded shackles are illegal. Do yourself a favour and buy a kit to suit your needs. It will transform the car