Spitfire vs Magnum Manifold

Depends on the power you want to make.
Under 350 hp with small overlap cams headers are not overly necessary.
The difference between manifolds are small power wise within 5 hp of each other shortie headers maybe 10 hp long tube 15 ish.

Id go manifolds or long tubes. The cost of the shorties aint worth the gain to me.
And if you plan on bigger cams heads etc.. in the future then long tube forsure.