Q9550 Core stepping

The C1 steppings will ussually get to 4.0, but the E0 are more likely to hit 4.0 on lower volts and temps. In my opinion, it's worth continuing to wait and look. Since you're in Isreal, I have no clue about online shops sending you stuff, but if there is an online shop email them and ask if you can specifically request that stepping or if they could notify you when they get them in.

Good Luck

on mine .. E0 is about 10 degree cooler than C1 ... idle only 25

IMO its worth the wait to get an E0 stepping. It's sometimes possible to get a C1 to 4.0ghz, but it's much easier with an E0 stepping.