So does it use any unofficial opcodes for performance?

(IIRC, the 6502 decoded instructions by bitmasks; say bit 7 meant "load" and bit 6 meant "move" or some such thing. So you could trigger combination instructions that'd still execute in 3 cycles but perform the work of two instructions that'd normally take 6. This might have been 6510-only, but I don't think it was.)