I would like to add something here again. Some points that are said against the Sigma 4/4 affect all Morgan cars because it is their principle nature. E.g. that you can not compare the road holding with a Lotus, I know it because I also drive a 2007 Elise since new with Rotrex supercharger.
I have had several Morgan models and the Sigma 4/4 is very reliable and unpretentious in my view. Also it is the Morgan with which I have never had ground clearance problems after 90,000 km. There is no Sigma 4/4 with rev hang. I would buy a Sigma 4/4 again immediately. With it you have the driving fun and you are not bothered by expensive restorations. All the service you have to do on the 4/4 is nothing different than other Morgan models. As I wrote weeks ago, just install the correct springs and the fun can begin.