Well I would say you will be fine with any SSD, they are all compatible with any SATA device. You will need a 2.5 to 3.5 bracket to mount it in the server correctly.
And yes you should see a good improvement in performance!
the Crucial MX100 SSD's are the cheapest per GB at the mo and very good, something more 'enterprise' grade for a server might be an Intel or the new Samsung 850 Pro drives which has a 10 year warranty and better benchmarked performance.