The A5 (0.16) coil is the pre-installed option that came with my Aspire Speeder kit, and in my eyes is the only one that should.
After the initial coil expired, I threw in the A3 (0.3) coil and took it for a spin.
...
Well my experience spun into a wall and I quickly fired up the computer and ordered 2 more A5's from the team here. This is because once you've vaped on the finer side of life - you'll have to drag me kicking and screaming back to the world of A3 peasantry.
Delivery was Saturday as requested, and I had a flawless experience :) Also echoing what Teressa has said re: coil packs, definitely would be nice.