I don't think that there will be much increase in the price of project cars in the next year or two. Here are the reasons, IMHO,
1) Supply of nicer cars--There are plenty of 'nice' cars that will come up for sale over the next year or two (death, divorce, etc)
2) The economy is still in the crapper. The net effect of this encourages people to pull their projects out of storage for re-sale while at the same time hindering the purchase of a 'multi-year money-pit'. (as a wife may call it
)
3) Germany was the driver of the price increase in these cars for many years, but if you read the headlines about the euro you see that not much help can be expected from that area.
4) Elections here in the USA--lotta people on both sides of the aisle are truly kinda nervous about this election, which is another reason to put off buying a 'mulit-year project' with related expenses.
So, while we may see price increases in very nice, well-sorted cars in the next year or two, project cars will see very limited upside growth as buyers will have lots of choices for 't's. From an investment standpoint, you'd be better off in two years by selling it now and buying stock in Apple (IMHO).
However, if you need it for parts for your other projects then the calculation is much different.