I intercepted two La7's last night with my pony. I certainly had the E advantage, and I used that to 'drop in' and say hello. The first one died to a pure six high speed pass. Instant death, too.
The second one took a two o'clock pass and I pinged him nose to tail. He lit up real bright, but the only result was black smoke. I dropped combat flaps, displaced with a high rolling yo-yo, locked up his six, and dispatched him with two short bursts that severed his tail.
So much for invulnerability.