The Su-35 deal firstly came out from Russia side(a Russian newspaper named "The business daily Kommersant"), both of DoD didn't admit it yet, i mean there's no official statements just rumors on the internet.
Anyway Su-35 is a good 3.5gen fighter, if true it's also not bad for PLAAF to equip 48x Su-35 fighters(Rumors said purchase 48x), and rumors said the truth of China to buy Su-35 only for Su-35's radar system and jet engines, wanna research 117S engines and RLSU-27 radar that Russia refuse to provide China alone. (U know China developing next gen fighter:J-20 and J-31, lack R/D experiences on thrust-vectoring jet engine)
So at last whether China will import Su-35 from Russia, i think it's still a good deal for PLAAF && China aviation industry, just 48x Su-35 to equip 2x new regiments of PLANAF and China aviation engineers can learn new technology to develop domesitc WS-15 jet engines.
1992, 1st group of 12x Su-27sk from Russia to join PLAAF. After 20 years, China Su-27sk started to retire from these 1st group.
Su-27ubk not retire, PLAAF need these two seats Su-27ubk to train new pilots. (Trainer for J-11B,now China still producing domestic J-11B,J-16 fighters)
PLAAF Su-27sk retired, 2009 old photos
After retire these old Su-27sk, now PLAAF still own 250+ J-11 and J-11B fighters, heavy fighter numbers still rise soon J-16(China version Su30mkk) and J-15(China version Su33) will join PLA together. Coz SAC can redesign and manufacture domestic Sukhoi fighters, China economy also can afford huge fighter groups.