HFM 2 Piece Rotors any good?

[No Crust Racing]

I've grabbed some 350z Brembos for the Silvia and am looking at rotor options, I was just going to grab some DBA 4000 series and good pads and call it a day as it's a lighter car already, but have seen these are not too much more for a bit of weight saving. Can't really justify DBA 2 piece prices. Car will be on slicks and will have a little bit of poke depending on state of tune. 

Who has used them for track work? I'll be doing sprint style driving. I see some people have pad knock back issues with 2 piece rotors though. 

HFM.Parts 324mm Front Two Piece Rotors Suits: 350Z Z33, Skyline V35