dude, for a start you've bolted the manifold on the wrong way round, it shoul point forwards

The downpipe fits
above the subframe & ARB there, so to fit you have to have the engine out or drop the subframe while holding the engine up.
Edit: Yep that is a std 16v system. cos of the big box it makes fitting tight thru the gap, if you can lift it high enough u might be able to slip it in from behind (steady!) in if the engine is not fitted.