Forget the Titanium Unicorn and go for the OVA version which has improved articulation.
Sinanju-wise, it depends. Generally extra-finish/titanium red looks much better than the silver used to replace normal white; the question is do you think it's worth paying much more for bling?
2.0.

Looks are subjective, and many dislike the retro style of the 2.0. I personally prefer it to the many other versions of RX78.
The 2.0 gives you the best articulation, very stiff (read: sturdy) joints, full set of weapons, and the corefighter with display stand.

At the end of the day, the decision lies in your hands. Google for reviews and pick the one that you like, not the ones that we like.
Ask Katoki

Don't forget the batteries for the GN drive 
Remember seeing some being sold online on ebay

i have it.. so, what the problem you want to ask?

hmm... which part are you mention? it is on head or chest part? mind show some screenshot of it?

maybe you accidently swap the both side... and do put the front chest first before snap fit the upper part..

Caution! Take note of this!
1.THE SMALL YELLOW PIECE  ON THE EXIA FACE CAN EASILY FALL... I RECOMMEND YOU TO GLUE THAT PART
2.IF YOU SWAPPING NORMAL MODE TO REPAIR MODE, DONT TRY TO REMOVE THE YELLOW ANTENNA BEHIND THE HEAD... IT CAN EASILY BROKE
3.ALSO THE HOLOGRAM STRIPS BETWEEN THE SHOULDER AND ARM PRT,YOU DONT NEED TO REMOVE AS IT MIGHT LOOSE THE SHOULDER BLUE PART

That all i aware... but it will best if you display as Repair mode as swapping the part can make some item loosen/broken... me planning want to get another one(normal ver. and not ignition mode) to display side by side