Buying a 97 318is

[halfthehalfer]

ok so i have found a 318is and it has a valve knocking so i was wondering if i should buy it for 900 and what it will take to fix it? the engine was blown but it is running now the timeing was reset and it running correctly i believe i have to redo the heads and put them back together but my two questions are
should i buy it and how much will it take to fix?

[restricted]

If it is in decent shape and you have the money to put into it then buy it rip out that under powered junk 4cyl and put a 6 in it I've got a 2.8 sitting with harness and 413 dme you will need a stronger trans drive shaft diff sooner than later but I will part with motor harness dme for $1000 and throw in a 391 open diff