the unified engines is part of what is bringing nissan out of debt and to pay their FORMER debts.... even though they arent legally bound to the debts from their 1990's deboacles.. nissan is still going to repay them, which i think is great.

With cars sharing the same body's (front midship platform comes to mind) and using the same engines. it makes retooling factories unnecessary.. Probabally the largest differences are in intake and exhaust manifolds as well as cams + tuning of the ECU's.. then again. with crazy variable timing these motors have. i wouldnt be surprised if it was just intake/exhaust (mostly because of motorplacement and that they choke their passenger cars more than the Z for example) and computer tuning, its very cheap to just change programs to the ECU... NOW what we need is NISSDATA from NISSAN or a large company that works with the current Z ECU