If you were looking to buy a Triumph TR7 five years ago, I would have said yes. Prices were low and seemingly no-one was interested in them. However, there has since been a huge amount of interest in the car and coupled with declining numbers, prices are now on the up. You could still buy one, and the prices could still increase, but not to the extent that they have in recent years. We'd never recommend buying a classic for investment purposes - much better to buy something that you're passionate about and enjoy it... and if it increases in value then even better.