i have 2 e30's an 87 325 and an 88 325is. the is is wrecked in front but all the engine parts are ok. what is the best thing to do? use the i head on the e block or what?or should i just use the i engine. the i has an automatic tranny with 168kmiles on it. the 325 has a 5 speed with 87k miles. what is best to do?