I went with an XS Power D4700 AGM battery that Jegs carries....other stores will carry this as well.
Cost me $279 with free shipping.
Fits perfectly into the 914 battery tray using the stock battery hold down clamp.
The battery has a ledge or foot on both the front and rear to allow this.
I don't have a rain tray on my engine lid as I'm a 914-6 guy, but it looks like there is plenty of room above the battery to allow for a rain tray.
Here's what she looks like:
Here are the specs:
XS Power D-Series AGM Battery 12-Volt
D-Series AGM Battery
Model D4700
12-Volt
CA: 760
CCA: 668
Ah: 62, 2000W / 3000W
Max Amps: 2900
Reserve Capacity: 110 Minutes
M6 Terminal Hardware Included
9.49'' L x 6.93'' W x 7.48'' H (Group 47)
42.2 lbs
For some the graphics may be a bit much.
I was fine with them, but decided to go stealth.
Here's what the battery looked like with a battery cover, some black vinyl and a Bosch decal off Ebay.
At 62 Amp-Hr, this battery has plenty of reserve power to run your lights, wipers and other accessories.