It was lion
https://www.eurocarparts.com/ecp/c/BMW_Z4+Roadster_3.0_2003/p/car-parts/car-electrics-and-car-lighting/electrical/car-battery/?444770271&1&1f6302da6a0cff7db8d100902e794032f38294a9&000020
The difference the other one was 20 mm bigger in length
A 12 v battery, is a 12v battery. The current rating (amps) is just how much 'oomph' it has got. As long as the battery isn't faulty or flat it shouldn't cause any issues at all.