Originally Posted by Silverstone

You need the spacer for the battery.

In my opinion, don't bother with Optima. They've had an apparent drop in quality over the past years.

Look at the Exide AGM. Cheaper and better. I fit a 24F instead of a 35 in my Z. Larger, more CCA, but fits perfectly. I know it's too late, but figure I'd recommend it anyway.

Exide Pure Lead, or Odyssey Extreme, which is the same as the Exide Pure Lead last I saw, are both good options as well, but are priced high.