4.5L petrol GU intercooled turbo upgrade

Hi everyone, I am new to the forum and have been sniffing around the great wealth of information here. Very impressed.

I have just recently purchased my first Patrol, a 1999 GU 4.5l petrol Ti. I purchased the car to tow my R35 track car in my sig to and from the tracks around SEQ 15 times a year from my home in Brisbane and the odd interstate trip to Bathurst/Eastern Creek etc once a year.

I like power and torque and plenty of it! I certainly do not want to be left twiddling my thumbs whilst lugging the gib lump around. Consequently I am considering a custom inter-cooled turbo upgrade and dual fuel lpg conversion starting next week. The guys from Mercury Motorsport who look after my R35 are awesome. they just happen to have a great in house fabricator who is a patrol nut, and mechanics with loads of custom turbo install experience.

If you're interested, check out my r35 build thread in the link below: (btw, hi to any SAU forum members lurking here)

R35 Build - Skylines Australia

Anyway, I would appreciate everyones thoughts on the following:

1. Turbo choice
2. ECU choice, tuning ability for petrol & lpg and cost
3. Need for upgrading the engine internals or not (when the job is done right, car is well maintained and sensible boost applied)
4. Costs of the inter-cooled turbo upgrade by those who have been there before and whether they were happy or not with the outcome
5. lpg conversion considerations, especially regarding turbo mod, and who to see in Brisbane.

Thanks for reading,

Mark