Does anybody know of a cold air intake that will fit my 88 E28? I added a new custom borla exhaust and muffler and would like to add a performance intake. Any suggetsions?

Kirban makes an intake for your car. You can find it here. http://www.nopionline.com/nopistore/dsp_parts.cfm?vpcid=948&vcatid=0030&vcatyear=1988&vmodelid=080&vmakeid=060&vL1id=0&&vtitle=BMW%20528%201988
It's not a cold air but you can try to fabricate your own.

K&N???

http://www.usdieselparts.com/knfilters/moreinfo.cfm/Product_ID/245991/sku/57-0197/name/K&N_57i_Entry_Level_Kit