You must be crazy, man, to store your bitcoins on the vanity addresses generated by the tool the source code of which you are not able to read and understand.
I fully agree and the full source code of VanitySearch is public. Anybody can compile it, the code is documented, you can read it.
The base key does not alter performance. VanitySearch choose a secure random base key (if no seed specified) only once when it starts. Then private keys are incremented, 6 addresses are calculated and prefix are checked. The process is simple. You have the possibility to choose new random base keys every certain number of key using -r, but it is slower and useless because it requires extra EC mult. It does not improve the probability to find a match.