I don't know what the first car pictured here is but I am familiar with the other two.
Back in the 80s. here in the States, there were several companies cranking out Porsche 550 replicas - all of them quite good quality wise. But the best one of the bunch was the Beck. And I believe that they are still in business. Here's a link:
http://www.beckspeedster.com/
Of course, the Beck used a tube frame that was REALLY stiff and strong. You may know this or you may not know it but in case you DO, bear with me as I explain what you likely already know. The transmissions on these cars is the standard VW 4-speed. It is turned around so that it faces forward. This puts the engine amidships and gives the car absolutely SUPERB balance. There are some caviats with this idea though.
#1. The tranny's ring gear needes to be "flopped" over so that the transmission will turn the wheels in the opposite direction from the original mounting position. This means that, once the trans is reversed, the rear wheels will propel the car forward. If you think about that for just a little bit, you'll see what I mean.
#2. The new mid-engined reversed transmission position requires the use of a VW SWINGAXLE trans and NOT a fully independent suspension that uses four CV joints. Here in the States, this means that the donor car needs to be a 1968 or earlier because, here in the U.S, the 1969 model saw the introduction of the IRS transmission. I suppose that someone could figure a way to mount an IRS but it would require a lot of fabrication that the swingaxle didn't require. Once dialed in, the swingaxle works really well anyway and it would be pointless to try to use an IRS.
Swingaxle systems suffer from a phenomenon called "jacking." When thrown into a very hard turn, the inside axle tends to tuck under the car and that, combined with the centrifugal force of the turn, wants to flip the car on its lid. Therefore, if the builder wants to avoid this, he will need to use a device called a "camber compensator." It's basically a piece of spring steel that ties the two axles together and makes them much more rigid. And OMG, the camber compensator will turn this little 550 replica into a rocket that takes corners like a go-kart. There are very few cars in the world of any class (Corvettes, Ferraris, etc) that can hang with it in the twisties. I have seen a lot of 550 replicas on this side of the pond and ALL had the camber compensator. Again, a link:
http://www.cbperformance.com/Product...oductCode=2819
The blue McLaren M6GT replica looks almost perfectly like a Marauder. Marauder was a company in the countryside outside of Urbana Illinois, here in the states, that made absolutely the finest replicas of the day. The company owner was a friendly farmer named Randy Barry. I knew him personally and he was crazy for Can-Am roadsters of the 60s as well as supercars such as the DeTomaso Pantera and the Lambo Countach. Randy had his own Pantera. (He let me drive it.)
Randy's special talent was in building fiberglass bucks, mock-ups and molds. He couldn't find a Countach to use as a pattern for his Lambo replica. So he lofted his mock-up from a 1/25th scale model and got it absolutely perfect.
In addition to the McLaren M6GT, he had replicas of the Ferrari 512S, (
http://en.wikipedia.org/wiki/Ferrari_512) the Lola T70, (
http://en.wikipedia.org/wiki/Lola_T70) a Ford GT40 and several others as I remember. Randy had a race car fabricator from Indianapolis Indiana, fab the monocoque chassis using Corvette suspension pieces and a ZF transmission. Then he installed his own bodies and the resulting cars were so incredible they could not be accurately referred to as "kits." Sadly Randy died of cancer and his very cool car company died with him.
This particular blue car that you have photographed looks like it MIGHT be one of Randy's car except that the stance is wrong, the wheels are way wrong and the front of the car sits too high. But the headlights are pretty correct for a street version that needs directional indicators. There should be some plexi covers for the headlights.
If this car is NOT one of Randy's, then it could be from Manta cars in Southern California. It was owned and operated by a guy named Tim LoVette, as I recall. Tim made a car called the "Montage" but it had different headlights. Originally, the Montage used a VW chassis as its platform. I met Tim at a Kit Car show in the mid 80s. Needless to say, Randy Barry had nothing good to say about Tim LoVette's car. Sadly, Manta cars has long been defunct.
Wow, this really knocked some cobwebs out of my noggin. I hope I helped.