Just to add some more noise to the debate....
There is another forum for Micro stuff that's very handy!
http://microrcracer.com/
I can't comment on the EMB-1 having never run one, but the GTB is actually pretty good out of the box.
There are a couple of good and cheap hop ups that are good for the car if you fancy it...and the only place worth looking for GTB upgrades is Thumbs designs....they do a simple and cheap kit with the most useful hopups....
http://thumbsdesigns.com/product/gtb...upgrades-pack/
Thumbs is Craig Harris, who's a Carisma team driver, and multiple micro national winner who's made all his tricks and tweaks available to the world. Go as far as you like with those obviously...but the most handy ones from memory where just the essential kit and maybe a weight kit.
Craig is very active on the micro forum himself, and always happy to help advise!