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