None of them are removed. instead the effectiveness of enhancements scales down.
http://wiki.cohtitan.com/wiki/Exempl...n_Enhancements
Also, enhancements with special effects, like the Numina Unique you mentioned, don't scale at all. Instead, they either provide a Set Bonus-like effect and go away if you exemplar more than 3 levels below it (Steadfast Protection Res/Def and the various KB protection IOs are good examples), or they function like a proc, and generate a 120 second effect (that refreshes every 10 seconds if in a toggle or auto power). The Numina's Convalescence Unique is of the latter type. As long as you don't exemp low enough to lose the power it's slotted in, you'll keep the effect.
@Roderick
hey all, just wanted to know which slots are removed from us when we mal / exmp in lvl? is it the slots on the right or left? im asking because i like using numnia +regen +recov and i usually slot all my recipes like that to the far left, thinkin the ones on right are lost when i go down in lvl. i also tend to slot anything that has endur red in it to the left too so i have as less endur issues as i can while mal'd down. thanks in advanced
RED CAP DAGGERS: if you want them red side on infinity, send a pm i have the mission to get them for dual blades.