How bad of an idea would it be to just install 05+ rear springs on my 04 coupe (I realize the front springs are the same) without changing the shocks right now? At a future point, I plan to go to Tokico D-specs, but my shocks only have 24k on them (and 4 years) and I don't want to change them right now.

 

Any setup gurus out there? It appears from parts catalogs that the front shocks are different from 05+ onward, but the rear shocks look to be the same for all years. Would I be introducing a lot of oversteer into the situation with a stiffer rear spring rate without a corresponding increase in front rate (due to shocks)?