RedPoint, I like your thinking!
I used mild salsa because, while my girlfriend is half Chicana (one set of grandparents are from Mexico and happily converse with me in Spanish), she is pure gringa. Actually, when I made my own dang cake, I wanted mango, and since I am tired of trying to find food that is actually flavored with food, my mom suggested that I made one more-or-less from scratch. I was at Trader Joe's and wanted a can of mangoes, but they did not have it, so I bought a bottle of mango nectar and a pound bag of chile mangoes--dehydrated. The cake mix was sixteen ounces and called for one cup of milk and a couple of eggs, so I put in two cups of nectar for two pound of dry ingredients, but without giving the mangoes more time to rehydrate, I had kind of a pudding with pieces of dried mangoes.
I loved it!
The chile was interesting...