hello. ive just bought a new my11 golf gti mk6 3dr. it comes std with an 8 speaker system and a touchscreen hu, the rcd510. anyway, i didnt get the upgraded dynaudio system, which was a $1200 option.
ive decided to put that money into a boston acoustics setup. ive had BA before and enjoy the quality of the sound. im not a bass head, i just like clean accurate sound.
anyway, ive looked on ebay and a reputable seller has some components i like from the usa. most notably the BA pro60se (ill use these up front) and the sc60 (ill use these for the rears. i already have a jl audio sub tube that i have from before.
i am looking at the gta 504 amp that BA have, its a 4 channel, and i think it might be up to the job

i will keep the stock HU, so ill need a line out converter, any recommendations?

basically, just asking for some advice with this, ive looked at the pricing, and i can get the above delivered to my door at a much cheaper price than locally. and those components seem to be what im after, unless u guys have other thoughts.
what issues will i come across with running the stock HU and aftermarket components?
cheers for advice