It will work just fine, I ended up with the OEM sized 51R Optima for a replacement but if I were going with a regular lead acid I'd have picked the largest one that would have fit under the hood and between the hold-downs.
Others have gone with a much smaller battery and they seem to work OK too, just not as much as reserve capacity if you accidentally leave something on or park the car for an extended period of time.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a