Had some dead pixels also... You need to replace the display itself, otherwise you are replacing an 10 year old one by another 10 year old one

Here is how to replace it: http://www.xoutpost.com/article/E53%...eplacement.pdf

You need a SHARP LQ065T9BR51U - and really exactly that one! Attention if you buy from chinese sellers, some are sending you slightly different ones (like LQ065T9BR51, LQ065T9BR54, ...) which will basically work but they are designed for a different viewing angle and therefore won't work well in the e53. So make sure you will get the right one.

DSP won't work with an aftermarket system - at least not out-of-the-box or in an easy way...
And using an aftermarket system will make some features unavailable or at least difficult to use (DSP, Aux Heating, Phone, BC, CDC, ...) - exceptions to all of this may be a Dynavin System which won't be cheap and I haven't used it, so no experiences from my side.