It'll be cheap if you source it yourself definately but if you're letting someone else do the job its an entirely different story. First they will get all brand new geniune parts, second mark up 30% 40% (just look at my charge rate at work... 135/hr to client)? And third, their time/contacts. These would make your 2-3k job easily 5-7k. But I do agree 8 seems unreasonable.
If I were you... try to get the full 12k and save the rest up and get a GTR ! I pack my lunch/cook dinner for more than a yr to get mine =P