Chaos- I gotta say, I love you man! In a Bud Light sort of way.
I wouldn't put much confidence in a 7S. Yeah I know it's lighter, by almost half, than the 14S I'm running, but I want cranking power. I'll pay 4lbs. for it.
Now if you're talking Shorai, for only $20 - $40 more, that's the ticket for these undertrays. And now that I've looked up the specs, on paper the Shorai is a no-brainer.
Shorai LFX18A1-BS12 - 2.3lbs. - 270 CCA (Cold Cranking Amps)
Yuasa YTZ7S - 4.6lbs. - 130 CCA
Yuasa YTZ12S - (OEM) 8.1lbs. - 210 CCA
Yuasa YTZ14S - 8.6lbs. - 230 CCA
The Shorai is actually the more economical battery when you look at the CCA's, weight, lifespan, and resilience for sitting.
The only problem is, I've seen 2 reports on our forum of these batteries frying and exploding in the battery tray. Rare. Maybe failing regulators/rectifiers as admitted in one case?