Looking for long-term review of someone who has done a PHEV conversion

Sorry if this belongs in the mod section but I feel like this kind of mod, improving FE, is more appropriate for a general audience.

I just bought a 2012 prius. It's still sitting in the lot.

One of my reasons for getting the prius over less expensive but still efficient sedans was the savings over total time of ownership in gas. 33 combined mpg of the elantra vs the 50 (or more hypermiling) of the prius turns into real $$$ over 5 years.

Anyway, I've been reading about PHEV conversion kits and i've come accross the engineer 4kv for 4grand with 30% rebate from government =2.8K. However, this extra battery, does not remove the limitation of driving in EV mode above 30mph so most of the savings come from extended blended driving times draining your PHEV battery.

I'm want to hear from owners who have done this conversion.

1- How much increase do you see on your daily commute? Do you use the EV mode more often or are these savings in blended driving?

2- How does this contant draining, recharging of your prius battery by the PHEV battery affect the lifetime of the prius battery?

3- Are you happy with your purchase AND- has it paid off financially? In other words did you recoup the cost of the kit on gas savings or are you projecting that you will in the next couple of years?

4- Finally, which kit do you recommend? is the 2kv enough for standard commutes or should I spring for the 4kv? 8KV seems excessive if I can't drive EV at full speed.


Look forward to hearing your answers and more questions that I haven't yet considered.