If you are going to stick with the stock turbo, then yes I would stay with the top mount. Tuning isn't going to make up for the fact that you wont be flowing enough air to make use of that front mount.

I know of alot of people using aftermarket turbos that are still running a top mount. It all depends on what your plans for the car are going to be. You need to address that question first before you start modding.