What year i heads fit an 87 ETA?

[Houston]

What head will fit my 1987 325 2.7L ETA engine? Based on helpful posts in this forum, I'm trying to improve the performance of this engine by putting on an "i" head. All input is appreciated!
If I don't get "i" pistons, will I still see an improvement in performance?

[MrM3]

you can use a 'i' head from any 2.5L M20 from 87-91, however you must use custom pistons or your compression will drop extremely low, i dont know if it would still be driveable or not, but it deffinately isnt a good idea to use stock pistons. you can however use 88 super eta pistons but it still wouldnt be ideal for performance as the comp would be in the mid to high 8's.

check out www.strictlyeta.net for more info