shadowhandYou don't have to boost using the amperage the pack can put out. If you let it dump some power into the main battery for a minute or so, you'll be able to crank the engine without too much trouble. Standard boosting procedure on large vehicles.
Pro version appears to be capable. From the kickstarter:
"The JUNOJUMPER Pro is almost compatible with 99% of consumer vehicles on the market today from V4 to V8 vehicles including diesel engines and marine applications. Our old jumpstarter can jump start up to 300A of cold cranking amps, while the JUNOJUMPER Pro can do up to 600 Amps, more than 20+ times with the 18,000mAh lithium polymer battery."
https://www.kickstarter.com/projects/junopower/junojumper-pro-the-ultimate-portable-power-source/description