If you're not looking to lift your vehicle, why do you want to replace the springs? Unless they're sagging there really is no need to get rid of the originals. If they are sagging then another pair of OEM springs is all you need.

I've got OME springs on my Gen II and couldn't be happier with their ride and performance. What sold me on them originally was that throughout my research, OME was the only company I found that actually engineered their products specifically for the Monteros, and designed & tested their shocks and springs as a package to work together. Most shock manufacturers that have shocks that "fit" Monteros are not specifically tuned for them - they'll make a shock that physically matches the original shocks and select an off-the-shelf damping rate based on the weight of the vehicle and the stock spring rates.