i'd park there everyday too. i mean really.. if its that much of a bother to her, she should start parking her OWN car there to avoid you parking there. Maybe you should start leaving her cards with REALLY UGLY HORRID cars on them, and write something positive on the inside.. some little tidbit about always thinking the grass should be greener, seeing the glass half empty instead of half full.. i know theres some quote out there that would be pertinent. Take morning glories for instance.. sure, looks like a nice vine with flowers.. in reality in quite a few states.. it is a noxious weed.
Or cards with extremely pretty cars on them, don't forget to include a roll of scotch tape so she can tape them up over her windows that face your car
Maybe print out some fake car awards.. "BEST OF SHOW" or "Diamond in the rough" and pretend to be all excited.. so excited you just had to share your 'joy' with anyone (including your neighbor, which is the whole point) and show her the 'award' while jumping up and down. Maybe she'll start doubting her judgement and leave well enough alone. being that she is 'snobby'.. i would try the 'car awards' first.
while it may not alleviate anything.. it would still be quite fun to do. (i also like the tinfoil idea!!)