Honda set it up so that the vtec engagment is very smooth. Who would buy a car that wasn't refined? it's just not marketable. If you weren't hitting vtec, the ecu should be throwing a code no matter what. It's a basica malfunction that the ECU should see. Honestly, your oil leak isn't that bad. I've had distributor seals that soaked the tranny before I noticed (2 days since the hood had been last popped).
I bought a del sol Si (d16z6) that was an auto. It was peppy, but nothing to write home about. I blew the tranny within a few months (long story) and ended up doing a 5spd swap. All I ahve to say is: THE AUTO TRANNY STEALS POWER LIKE A MUTHA! It's unbelievable the increase of power transfer.