I did the build by hand, so no way in hell was I going to try to add it up. That 395 XXL is going to be a cost multiplier the likes of which Rockefeller has never seen.
Well, on that cue I just ran the design through MegaMekLab...and first of all it turns out to be half a ton overweight even with the targeting computer moved properly into the body where it belongs. It's that selfsame engine; you skipped a "round up to the nearest half-ton" step between dividing standard engine weight by three and then adding 50% again to account for vehicle shielding, didn't you? Because that's where the difference comes from; MML lists the engine as being 25 tons rather than 24.5, which makes sense for (49/3 = 16.33... rounded up to 16.5, x1.5 and rounded up once more for shielding).
It's not a big deal in this case, however, since it can be fixed by addressing another issue I hadn't noticed at first (and which MML doesn't recognize yet either)...CASE II isn't actually valid vehicle equipment. You can put it on 'Mechs and fighters, but that's it, and there are no actual rules for how it'd even work on conventional vehicles either. So replace that with regular CASE, which
can go on vehicles, and both legality problems disappear in one swell foop.
So...that cost? According to MML, you're looking at a BV of 2,634...and a 642,720,833 C-bill hit to your bank account per unit. (It's indeed mostly the engine; it makes up over 97% of the unit's
base cost even before dropping the final tonnage multiplier of 7.4 on everything.) Ammo is extra, of course, but by the time you're rich enough to spring for this thing instead of the DropShip you could also buy with this kind of money I'm reasonably sure we can legitimately file that under "Peanuts". ;)