I bought a 1995 eagle talon tsi awd with a turbo and it runs but the car doesn't run right in gear?

Well i bought it for a project car it starts almost fine. but it over heats even with a new thermostat. and it idles fine in neutral or in park but if i put it gear reverse or any other gear it looses power wants to die doesn't move unless my foot is to the floor and then still doesn't go anywhere but it does pick up speed after a block and then overheats lol and it has a dent on a pay under it i think its the transition pan it only has 144,420miles on it plz help me...