Save yourself a lot of time, join theturboforums.com and post this same question in the Mopar tech section and read hundreds of topics of owners that have done this before you. Spend about six months researching before spending a dime. Understand the pros and cons of each setup (front/rear). 600ft/lbs @ 5,000 RPM is 571HP, this is a reasonable estimate if you keep your RPM's low. Figure out what exactly what your block can hold and what the limits of main driveline components are, there is no secret limit of boost pressure, but the higher the boost the more critical the tune that is required. One T6 BW S475 1.1AR will make all the power you want and more. Look into the economical GT45 t4 setups, we have a very large thread with years of testing on these turbos.

My advice, 1x GT45 70MM, 2.25" off collector merged to a Y-1.75-2" to turbo. 2.5" cold side to front. Make sure everything is wrapped & coated from the header to the T4 flange. This setup will easily make 500rwhp on a 360ci engine. Forget everything you know about N/A engines now, because very little applies. You say you want twins, sure, have you designed a system to return oil to the pan? Twins have twice the amount of failure points on your return system (major downside of remote mount solutions). Only way to get around that is to build a very large oil reservoir/oil cooler system in the trunk and not utilize engine oil. At least then, if a fitting rattles loose (which one will eventually, I lost 6 quarts within a minute or so);, you're out nothing but one or two $200 eBay turbos with cooked bearings.

You will be way, way, way ahead to just run flipped manifolds and stay with a front mount. B/RB Mopars do not have that simple solution.