Beginner help with .dae files in blender.

I recently started 3d modling, i started making a couple models in sketchup, but that program has some limitations when it comes to modeling so now ive started using Blender.

The problems im having is when i transfer my models from sketchup to blender the mesh of the model changes.
And this model has 160.000 faces when i transfer to blender which is ALOT! but when i try to lower the poly count it all becomes a big blob.

This is wireframe screencaps from blender and sketchup.

Is there a way to lower the poly count without the model deforming and is there a way to fix the wireframe problem? or are the models ive made in sketchup a lost cause?