idealy id want the car to go about another inch or so lower at the back than it currently is, (2" lower than stock) but i'm worried that this lack of travel might be fucking up the roadholding ability.
Yep. Sure will. Most people don't quiote understand that mega low cars may look cool to some, but unless the WHOLE SUSPENSION SYSTEM (including the chassis) is engineered as such, the ride, handling and geometry will be worse than a slightly higher but better engineered system.