AWD Coils On Rear Of FWD

[xcmtb83]

I know that the AWD Vibes are taller than the FWD models. Is this additional heigth due to a taller coil springs or just a spacer to achieve the lift? If the coil is in fact taller I am wondering if a person could swap out the FWD rear coils for rear AWD coils. I would think this would be nice if a person always had somewhat heavy cargo/camping gear in the back of their Vibe or had a a hitch mount bike rack and multiple bikes commonly onboad. A taller spring or a stiffer spring would take the weight better and restore more factory like handling. What are your thoughts?