Right now i have an alpine cda9805 from 1999 in my car. My buddy wants to sell me his pioneer which was one of the most expensive deck they offered two years ago at around 300$, hes sellin it to me for 100. I was just wondering if just because the deck is newer will it sound better? since the pioneer has newer technology. Plus it has a hell of a lot more audio options and EQ settings than mine.

Not much difference in CD in my opinion. Butons & whistles and out put makes the difference. Also some tuners are better than others. Just depends on what you like. I rarely buy the most expensive stero. Make sure speakers are upgraded and hook ups such as amps are done right. IMO

EQ settings do make a difference. The better bang for the buck is in the amp and speakers. I would also recommend sound insylation in the doors.

I was just wondering if it would make my subs sound better, all my speakers are upgraded to alpines.

better radios will make a huge difference in sound. In some cases it gives your better control by eq'* and crossovers and a higher voltage preout with less resistance will give your amps a better signal which means more output so yeah... Newer is sometimes much better