An eheim 2217+ is available for about £90 and after media is taken into consideration would give you over 6x turnover which would be fine. I'd only aims for 10x if you have heavily planted tank or extremely messy fish.
Why not get the 2217+ and run it together with your 2213? That will give you more than 10x turnover if thats what you wish.
Absolutely no point getting the fx5 because you'd have to turn it down to under half the max flow so your wasting money, also as mentioned, the pipes wont fit into the precut holes as the pipes are monster thick.
Andy