What boat are you planning to tow with you're new LC? I tow a Trophy 2002 with my 200 series Landcruiser.  I have done nothing whatsoever in regards to suspension and it sits perfectly level and tows like a dream.

ive got pedders heavy duty springs raised 50 mm and foam filled shocks on my prado and they carry my 6.5 meter glass boat no problems

go air bags adjustable to what ever your towing 

commodore allrounder 760 with a 225 hp honda on the rear end, i hear you with the towing , alot of power and torque, just want to make sure the back doesnt sag over time

there are pros and cons of both.  If you put heavier springs in the back only, then when the car is unladed, it will sit high (might not be a problem to some) and it will ride a lot firmer and stiffer.  This extra height would be handy off road, if that is what you are into.  That said I know of plenty of people who are running heavy springs in the back only and aren't worried about ride quality

with Poly Airbags or the like, you have the flexiblity to leave the springs standard, and then adjust the rear height via the airbags depending on the weight you are running.  Just be aware that the airbags don't last forever, a set of mine rubbed through, just though the spring moving.

If it was me I would rip out the standard suspension and put in quality gear like ARB or Bilsteins with a 2 inch lift and then go the airbags for towing.

should`be a great car mate, they are a weapon tow vehicle

I'm a tradey, and a trailer basically stays attached to my cruiser at all times, albeit I am not towing around a 7.6 mt boat regularly, I would maybe wait until you get your Cruiser and see how it sits on the towball, in saying that there are 2 different stock Hayman hitches you can get fitted by Toyota, I cannot remember which one I got fitted but I think it was the one that sits lower. I wouldn't have thought that there was a huge need to rush out and modify a vehicle that was purpose made to tow such loads.

it would be the airbags, I've been in more than one cruiser where heavier springs have been put on and have experienced the compromised ride when not towing. Airbags are adjustable as has been said, the better option I think. 

i wouldn't worry to much about it Matt - see how it goes. I thought you would be getting the kdss suspension anyway? Nothing that a trip to exxy and back is going to kill. If it does start to sag then spend the money on it in three years. Otherwise put the $2000 into boat fuel.

My 100 series came with kings and bilsteins and whilst it is nice, I think the ride in the standard was probably a bit nicer.

I am a bit suspect that the rear springs might be pretty bloody stiff in mine though.

Had the sag problem originally and the airbags sorted that out.  Being adjustable is a big plus.

I also have a 670 Allrounder and tow it with a 100 series. The standard springs handle the weight with ease, I have poly airbags but only ever inflate then to 8-10 psi, anymore and the trailer doesn't sit level.

With the extra weight in the back of the car and boat travelling Nth you would brobably need to go up to 15-18 or until they sit level on flat ground. I didn't go with heavier springs because of the harder ride when not towing.

 Don't know how the KDSS system would handle the weight but as stated wait till you try it then decide. 

yeah might lean towards seeing how it goes on the trip to exmouth, let things settle etc and look into it if needed

Let us know how you get on...I'm sure there will be no problems.

Matt, check your warranty, some manufacturers do not allow towing in the first 1000km.

alfred will be making sure i have a few k's clocked up before exmouth,

I have the GXL without the KDSS. Sagged it's arse with the boat on and low beam was blinding everyone. That said I have my trailer rigged to carry 200kg on the tow ball so she tracks straight and never gets that shimmy up on the trailer.

Only cheap bags..$500 fitted..had them for two years now..no problem.

Dont use a trip to exi to test it out..if your car rides crap then thats a long way to drive. 

Just hook up the boat and see how much the rear goes down. Do it at night and judge the extent by the low beam of the headlights.

Be aware if your car is a new twin turbo diesel they like to use a lot of oil in the first 20/30,000km. I towed to exi with mine at 5000km and on the way back the oil level light came on 100 km from the next servo.

I have polybags on the Jeep now for over 5 years and still love them, great for when you want a normal ride and then gives you the extra boost when towing a big tub. ARB Welshpool did mine and I can recommend them highly

Tony

Had airbags on a 100 series towing the abrolhos 8000, 3.4t, after discussion with ARB because i could deflate when not towing and keep the good ride and then when towing inflate, not only to stop sagging but to keep the boat trailer and car horizontal.

When braking, if the trailer causes sage it reduces steering capabilities and if too high then can cause jack knife, so the airbags allowed me to get the trailer and car on the same level.

Regards

certainly some good advice and seems definate to stay away from the heavier springs, they drive so nice so dont want to compromise the drive too much.

new heavy duty raised springs and airbags

Just my 2 cents worth Matt (may be obvious to you of course) but, just make sure you distribute the weight of your luggage evenly in the boat (less in the car). Doubt you'll have any trouble with the new cruiser. I'd say, look at the suspension later down the track.

if it aint broke dont fix it. I wouldnt worry about it until it was noticeable but thats just my opinion. one would think a brand new 4bee would have ok suspension straight off the bat. If you are going to bush bash would probably steer clear of the airbags, leave em for the highway.