Retro and others are still getting years outa theirs so I'm buggered if I know what's the go.
From what I have experienced and read about, the batt needs at least a 20 min ride just to replace the power of starting. Temperature plays a big part of battery life too, any extreme temps cold OR HOT drain it quickly, and batteries lose their charge naturally at a constant rate in "normal" temps anyway.
All originally supplied new in Australia Harley Davidson models came with factory security with 2 proximity fobs.
Does the 08 twin cam have the alarm system fob thing?
It's certainly function over form 😁👍