An ability like this is toughy to balance, obviously since the cards you mentioned are parts of many combo engines.
That said, having to sac three permanent s before gaining any mana makes this ability very under powered and creatures are inherently more vulnerable to removal than artifacts or enchantments, so you could probably beef up the body its attached too without raising the cost.
Frankly, I was wary of the effect given its inherent potential as a combo engine but considering the setup necessary I’m thinking of dropping it to a 3 mana 3/3. Maybe tack on Hexproof.
I wouldn't go with hexproof, because making a combo enabler untargetable makes it too strong. At a 2BRG 5/5, though, you could reasonably add Menace, Deathtouch or some similar combination and still be reasonably priced.