I would say no more than 6-7 k..at the end of the day its on a q & needs a rebuild if yu get another bottom end it will prob need a freshen up anyway & gasket set & so on so your gonna need to spend a bit of cash to get it right...there is 2 in the for sale section on here for 11k or there abouts & they are runing & hpi clear so if you spent any more than 7k on the q plate by the time you build the engine it will owe you aout 9-10k..for another 1k or there abouts you can have a car with no history..