It is a tricky one to answer, regardless of the equipment. So many variables involved. For speakers, placement is often the most important part. Cheaper speakers properly placed can sound better than very expensive speakers poorly placed. It is an entire science on its own.
Enjoy the equipment you have. Listen to records, both new and second hand and then decide where to upgrade most. A mid range cartridge can help an entry level deck. Your system should sound good on any source.
Vinyl can also be hit and miss. I have some really terrible pressings in my collection that will never sound good and some that simply blows me away.