Obviously both are affected by the market, but I don’t think one affects the other since the buyers of each have different reasons for buying.
I see a SFR as desireable to a couple that has kids. If they feel that they are going to be priced out, they will jump into the market thinking that they need space for their family and they don’t want to lose the chance at getting their “nest”. I think they will hold on longer for the kids than someone who has a condo.
A condo is different because in San Diego, they are the lower priced alternative. I think this has led to alot of speculators buying them, but it also has led to alot of people buying these because it’s the only thing they qualify for, and this has caused the “price/what you get” ratio in condos to soar.
When the market sours, condos are going to get hit first and the hardest because of this, but I don’t think it’ll directly affect the SFR market, rather they’ll both be affected by the market on their own.