Marina Slim S series (S10, S15, and S20) Filters?

[Brian_Nano12g]

Just wondering if anyone used these Marina Slim S filters and if you modified it in any way to use a sponge, biomax, purigen, or something other than the cartridges? How does this filter perform? I like the slim form factor and that it seems like it would be quieter than an AC 20 for example, due to the motor being inside the aquarium. Anyone care to share the experience?

Thanks!