Probably 95% of any performance improvement there is due to the SSD.

And no worries about "performance degradation" over time, at least not with the current crop of drives from Intel, OCZ, and a select few other brands.

They all have firmware which self-optimizes things on the fly and in the background. TRIM would gain another 5-10%, perhaps. But nobody other than micro-benchmarkers will ever see the difference in real-life.

EDIT: Well, perhaps on the Intel, since it is so slow at writes even when new. But their firmware is pretty good, too.

Cheers