I have just become the proud new owner of a 2002 4.8L GU

A few questions:
1. I am hoping to fit 34 x 12.5 (or similar) muddies, once i have done the 3" lift. From what I have read on this form, it seems that there shouldn't be any problems. does this sound reasonable? (legalities aside)
2. How does the rear "barn" door hold up with the added weight of 34" spare?
3. Any recommendations for workshops to install the 3" lift, in Melbourne? I see that Cheezy Racing do lifts, and I have heard good things about them. Any comments?
4. I would be interested to hear from anyone that has done an LPG conversion (replaced the main tank, and left the sub tank), to find out what sort of range you get out of the ~90L LPG + 36L petrol, as apposede to the stock petrol combination
Thanks,
Jonty