Boy is there a lot of wrong information in this thread.
First of all, Hennessey does not hold a Guinness record for production car top speed. They made up their own record. If you watch their video, the record is given by Racelogic, which is just a company that makes data acquisition software.
They DO hold a Guinness record for 0-300km/h, but it is not a production car record, it is just listed as "two seat hypercar". The reason they didn't do a similar thing for top speed is that there are loads of salt flat cars in the same classes that have gone over 300MPH, which is near impossible for a road legal car, so the production car record is the one that matters.
The car is an Exige with a twin turbo GM 427 (LS) engine. YES IT IS still registered as a Lotus. There are numerous references for this all over the Internet, from magazines, to Wikipedia, to the Venom's own website where the disclaimer at the bottom states that it is based on the Exige.
Koenigsegg started out using Ford modular engines, but they are now building their own engines, although they are still loosely based on the Ford design. Not the same thing as bolting on some aftermarket parts and claiming you made it.
I personally think the Venom is pretty cool, the issue for me is that when they start lying about it and trying to claim records for which they aren't eligible, it is insulting to those who are spending the time and money to engineer true production cars.
Not sure if you guys realize this, but it is orders of magnitude more difficult and expensive to engineer a car for legal sale than it is to design one that can go 250+MPH. You have to meet crash test requirements, emissions requirements, and a whole slew of general engineering requirements like stability control and idiot light placement and headlight design and power window switch designs. You can read all about the US requirements here: Federal Motor Vehicle Safety Standards and Regulations
. In addition, to sell it worldwide, you also have to meet all the UN requirements, which area similar, but different enough that many of them require separate tests.
If Hennessey wants to claim to be in that circle, lets see their crash test results, or their EPA type certificate. Otherwise STFU and lower the price and sell the thing in the same class as the AMS alpha GTR series. It would still be cool, and they could still make money, without even acting like scam artists.