HPI is a good car, but only for beginners. If you look into racing your car in the near future, I'd recommend you with Mugen MTX-2, Nitro TC3, or better yet Serpent Impulse. These car will serve you the purpose and save your money in the long run. I have the HPI RTR3 RS4 as my first car. Spent a fortune on hop ups hope to make it as good as those other cars. Disappointed... I now own Mugen MTX-2. Its price certainly is a lot higher than of Type SS, but you'll own a car that last.
O.S. 12CV series is good engine. It'll last you a lifetime--only if you don't abuse it.
Well, if you are going to buy O.S. engine, buy 12TR. Its price will be relatively close to CV's.