I dont know but I assumer there must be a big sound difference that is why one is priced so much more
But in buying any audio component be it for home or car I always look at the specs....look at the specs of a few subs,,,power handling etc,,,and then make an informed decision...i researched on and off for months and hours at a time when I rebuilt my system recently....and got some good help from a couple of brothers.........but no substitute for alot of research.......i literally mean hours on end....
about 2din pre I dont know maybe some crappy chinese ones...I would advise buy what you originally wanted a good high quality pre and in your price range you should be able to get a quality pre....Personally I like warm sound so also prefere pioneer pre although the alpine pres are like almost twice as clear but too bright...
my other components in the car from amplifier to sub actually make the listening a pleasure with an awesome mix of clarity as well as warmth...but I stumbled across the setup and changed the amplifiers and components like 3 times in the last three months...
i still have some fine tuning to do and a couple of things to add...but good luck bro and I hope inshallah you end up with a system that pleases your heart.....