Agree with all the comments thus far. The ones I found most important and "must have" for me:-
1. Definitely the higher travel cover. It is amazing what fits under here. (awning, side walls, ground sheets etc which I store on top of the dust cover and under the travel cover.)
2. The Lido Junior stove is fantastic. I hunted around for an alternative, but came back to the Lido, even though they are not cheap.
3. I think the drop down legs are standard?, but well worth having.
4. Unless you carry 25 litre jerries, it is well worth having the standard 25L holders made for the 20 litre, otherwise they will be a PITA flopping around in the bigger space. Keith suggested some people like to use the extra space behind a 20L jerry to store things, but not for me. I am glad I had them changed.
5. Stoneguard extensions - stops a lot of damage, although on our trip to the Cape last year, I still found parts got sandblasted, even with full length mudflaps I have fitted under the draw bar/toolbox area. e.g the 30mm on the leading edge of the mudguards not covered by the extension and the lower edges of the front of the trailer still copped it. I am in the process of making up some extra mudflaps for the back of the vehicle to try to minimise the damage. It was a real pain fixing it all up from the last trip.
6. Treg hitch (or similar ie D035 if Keith will fit them) I have had no problems at all hooking up the trailer.
Good luck with your Tambo purchase. You will find Keith and Amanda fantastic to deal with. Nothing is too much trouble. The Tambo is a great value for money trailer and as tough as nails. It handled our Cape trip including the OTL without a whimper.
Regards,
Dave