Hi,
If you do look and search through this forum, a 'few' people have indeed brought their US specification "car which has a UK equivalent" over.
The Toyota Prius is such a car - it has a UK specification version. Thus, it's what I call a 'bread and butter' car - i.e it's nothing special and I'd say isn't worth the time hassle or money to bring a US version over as you could sell it off there and purchase a UK one for around the same price.
Importing USA vehicles only becomes 'more value for money' when it's an 'interesting car' - there's a big community of USA car owners here in the UK and importing cars happens all the time - we've just picked up another F150 Harley Davidson Anniversary edition truck and another good friend has also recently picked up a 1969 Pontiac Firebird that's been restored very very well. If the need arises to sell the cars on here in the UK, there's a big community of potentially interested buyers. There's zero demand for a 'normal' car or one thats got a US and UK presence.
The rules have changed recently, but I think for car's it's still pretty much the same. Import Duty, VAT are costs you'll need to check to see if they're applicable to your particular car. I don't know much about Hybrid's in terms of importation requirements though.
Here's some sites to help you get started
I'd say read the official government pages first
https://www.gov.uk/importing-vehicles-into-the-ukThen,
http://www.import-car.info/I'd say then speak to a UK Toyota dealer and a USA Toyota dealer, and see what they say about specification differences between the two are and any parts required to swap. Then look at Toyota online web forums about any discounters, special deals, tips and tricks etc to see if any apply to your car and situation and evaluate.
Your employer 'might' not understand all the costs and procedures involved, so triple check with them they'll actually pay to bring it over minus the conversion costs. I'd be tempted to say to them forget importing it over, they might say they're not paying for the return leg in a couple years etc and ask for an increase in your salary or a UK car allowance.
Cheers, DtM! West London & Slough UK!