1150 to 1150ADV: How to do?

[Warthog]

As some have previously read, I now have a Y reg 1150GS. I chose this model for a few reasons:

A bit cheaper than an ADV.
Lower seat height.
More comfortable for my girlfriend on the back.

However, one main reason for buying the GS, initially, is that we want to do a trip round Argentina/Chile next year , and if we like the more adventurous side to riding, perhaps elsewhere too.

Obviously, on paper the ADV would be the wiser choice, so what should I get in terms of bolt-ons (praise be to the internet, online shopping and all who surf upon them. Amen ) to bridge the gap?

I'd like to lay my hands on either a 2nd hand ADV tank, or even a touratech tank and some H & B bars. I'd like to also get some sturdy luggage, but they're all so expensive! I may have to go for plan G and get some rivets, an angle grinder and some ally sheet!

Do I really need to get anything else?

 

[snoopy]

The ADV has higher travel and a different beak at the front. The standard BMW bars for the non-adv from dealer are crapper than the ADV ones so go for aftermarket but stay away from black as they will get scratched to hell.

Really though, save the trouble and sell n buy an ADV.

 

[Warthog]

The ADV has higher travel and a different beak at the front. The standard BMW bars for the non-adv from dealer are crapper than the ADV ones so go for aftermarket but stay away from black as they will get scratched to hell.

Really though, save the trouble and sell n buy an ADV.

I realise the ADV is more the spec I need and in fact is probably overkill, but I just don't think I'm tall enough to comfortably manage the weight: right now, I can get both feet flat on the ground, and I don't want it any different, also the back seat is more comfy for the lady.
In fact, I looked up a luggage maker (Bernd Tesch) who makes ally panniers with removable, flat jerry cans that would double the fuel carrying capacity of the bike and therefore save any expense on a second ADV tank as well as distribute the weight more evenly around the bike (22l front, 20-26l rear).

So rally I only need that H&B bars and a set of metal panniers (That I would need anyway). So whats so bad about the standard bars and what should I consider as replacements and what would be the advantage of this move?