living in lake elsinore, which fastrak to get? (moving to, discount)

[crackers8199]

as the topic says, i'm going to be moving to elsinore and will want to grab a fastrak transponder for trips to SD, LA or OC...but (a wrinkle), i drive a chevy volt so i have the ability to use the I-15 lanes in SD county for free, or the LA metro express lanes (after march 1), or the 91 express lanes (but i need a transponder and will only get a 50% discount M-F, 4-6pm, eastbound)...i do want the ability to occasionally use the toll roads in OC if i want to, which is why i want the fastrak tag (in addition to wanting access to the 91 express lanes).

so, this leads me to a few questions:

1) which agency should i get my fastrak from? i figure i have a few options...

- SD I-15
- 91 express lanes
- the toll roads
- LA metro expresslanes

2) after march 1, do i still need a transponder for the metro expresslanes or will that go to free with just the green sticker and no transponder?

3) if i get a transponder from somewhere other than the 91, do i still get the ability to use the express lanes for free or will my transponder be charged every time?

4) if i get a transponder from the 91, can i still use that to pay tolls elsewhere even though i'm getting most of my trips on the express lanes for free?

if anyone can give me any other tips or suggestions, they'd be appreciated...thanks!