I like the honeycomb/carbon idea, but the cost shoots up so fast...that stuff is so expensive and in the end, you will only save about 150-200 pounds...great as long as someone else will pay the $20,000 difference in price! The other problem is that you don't really have any good hard points for engine or suspension bits.
Two guys can easily pick up the Centaurs' tub (weights about 300 # with all the fiberglass) and you can weld a hard point anywhere you need to.
Get it on the road as cheaply as possible, THEN worry about making it faster or lighter. I know you will have a lot more fun DRIVING a 1,400# car with a 100hp engine that you ever will dreaming about a 900# car with a 300 hp engine. I'd even venture to say you'd never even know the difference until you got on a real race track, because the 1,400# car will still be in the fastest 1% of every car on the road, and in the top .001% of turning and stopping.
Without a doubt,the number one reason thee cars are not getting built [okay number 2 after money!] is analysis paralysis. "My car is gonna be soo bitchin because I'm gonna use titanium A arms and one of those $50,000 formula one steering wheels"...Those are all things you can add on later...get it on the road first! You will be so glad you did, you will probably forget about all that other stuff!
We have all been in fast cars, but to me and everyone else that has driven these things, it's not how fast you go that knocks your socks off...it's how fast you stop and how fast you can corner.
I've raced fast, light sevens, but get A LOT more enjoyment out of just driving the ol' Pirate....you can do it everyday if you live where the weather allows, and I get treated like a rock- star wherever I go...it may even get you that job you always wanted!
In fact one night, just after I got the car running, we went to see a friends band, Ex-voto, [ http://members.aol.com/exvoto69/index.htm ] play at the local club in downtown Long Beach on a Goth night. There was a extremely small space, no more than 11' directly in front of the club. We had parked around back, but I asked the bouncer if I could park in front. He replied "Buddy, if you can fit there, you can park there" So I went back to my car and maneuvered it into the small space right in front of the club. Later that evening, My wife and I were talking to our friends, the band keyboardist, Linda and the bands singer, Larry in front of the club. this guy walks up to us, and I could tell Larry was getting ready to sign an autograph. The guy looks kinda sheepishly at Larry, and just as Larry is getting out his pen, the guy asks Larry "wow that is so cool..is this your car?" I think Larry was a little embarrassed, because he walked away, but Linda, my wife and I thought it was pretty funny!
try doing that in any car that cost $7,000!!!http://www.usa7s.org/aspnetforum/upload/1810344900_v27.jpg.JPG