my first analog setup , some advice please

Hello friends.. So here is the story
I recently bought my first ever analog setup , and little over a year ago i started my first hight end stereo system. I bought every component after a lot of reasearch and i’m really happy the way it sounds. So for my analog setup , i got a VERY good deal for a Pro Ject Xtension 9 evolution turn table , Van Den Hul DT II Special cartridge , and Pro Ject Phono Box Rs pre amp. I’m a little skeptical about the phono box, i asked my dealer if he things that i need to get a better phono box , and he said “ not as long as i have the Van Den Hul Dt II Special cartridge “
so.. Quastion
Do i need a better phono box ??
I know many will ask “ does it sound good ?“
and the answer is yes ! and i’m really happy with what i payed , but like i said , i’m new to this and i feel there is a lot of potential for my system..
the rest of my gear
dali euphonia ms5
edge nl10 amp
benchmark dac3 pre amp
ps audio p10 power plant
and all around good wiring


Tell the dealer to let you demo a better phono stage at home. You are on the right track with the cartridge and phono stage being your weak links. The rest of the system is very nice. Cheers,
will do !! thank you @sbank 
how about the pro ject xtension 9 evo? is it  decent for the rest of my system ?? don’t give me wrong , i love the way it sounds ,, and i listen some very good digital recordings from my mac and i’m really happy the way my system sounds  sounds ,, i’m only asking because i’m new to the analog world , and just because its vinyl it has that “sweetness” over the digital recordings , wich i love , but i want to know were i’m at with my analog setup and ways to improve it in the future. 
@dimitris7I haven't spent much time listening to that table but recall a dealer telling me that he was frustrated because he liked better than many others he sold in same price range but felt many didn't give it fair consideration. FWIR, it has a nice arm for it's cost.