Plug and play Mike. Shorai's are lithium iron phosphate chemistry that charges very similar to VLA and AGM batteries. Lithium ion is too unstable for mobile use unless heavily guarded from damage. Pretty explosive if water is introduced internally too.
The actual Ah capacity is less than my original 18Ah VLA, but you only want to draw one of those down to 50% or 9Ah capacity. The available cranking amps and voltage sag drastically a VLA or AGM battery is discharged below 80%. A lithium iron battery is pretty consistent from 10-100% state of charge, so even if it is super low, it will still spin the engine over.
I'm really looking forward to putting them in the trailer and loosing 500lb of lead from my battery bank. The lights will be brighter too as the operating voltage is higher to start and stays higher down to 10%.