Vintage Dual 1228 Turntable : worth to upgrade cartridge ?


I have from my college days (1977) Dual 1228 with original fitted Shure M95ED cartridge .  It is maintained well , not used for about 20 years in between , but just cleaned , lubricated , resoldered some loose connections , etc and just runs great for me. 
I am not too much into analogue , so not planning to do big time investment into new TT , Phono preamp , but if  can get larger benefit by replacing the Shure M 95 ED with some new cart upto $ 200-300 , I would like to do it . 
My Phono preamp is very low end Cambridge Audio MM 551P . To go with new upgraded cartridge , I may even consider to buy used Phono with budget of $1000 . 
I would appreciate advice form FMs here , where I should spend my money to get most benifit on sound improvement . New cart , new phono ? 

radni
 I must have 6 Duals,I ran a 1229 and a 1219 for years,my last cartridge upgrade years ago was a Goldring 1042 or 1022.A couple years ago I installed my Signet AM50 on my Dual and it sounded very poor compared to on my secondary P+E table let alone my Rega.I would plan on replacing the Dual or staying in low price cartridge range.Spare headshells are the way to go,I have about 5 for the P+E and the old Shure V15 sounds good.Duals were good in their day but just can't produce soundfield.
Playpen,

Thats total Hogwash. A properly set up 1229 will blow the skirt of most entry level tables. Mine certainly does and it isn't just my opinion either.  Come listen anytime.  If your P&E table is vintage, it was built by Dual. Dual bought P&E back in 1972, and built their tables until about 1978 when P&E was phased out. 

My Dual 1229 using a Grace 747 sounds better than my grease bearing Garrard 301 using a SME 3009.  Both were infinitely better than my Linn LP12.  

Norman
Radni,

The Dual alignment guage is necessary to properly set up the Dual arm.  It can be done without, but it's a real pain.  You can often find them on eBay. I will see if I have a spare I can lend you. 
Maybe that's why Playpen had such a negative experience with his Duals. 
N. 
I remember that my Dual 1228 when purchased from a dealer , it came with the cartridge M95 ED already fitted on it . I have never removed or loosened the mounting screws or tried to remove cart from shell. So chances are  it is fixed properly. So I will download a protractor and then check if cart fitting is ok, then decide further. 
Yesterday I recalibrated or readjusted from scratch the tone arm , counter balance, strobe, and set the tracking force at 1.25 ( from 1.5) , fresh  Shure stylus RS 9E is fitted only week ago ( I had one in spare from the time I bought Dual ) . To my surprise , there was a great improvement in sound , background noise came down ,  which even my wife noticed and told me without even my asking . 
I think Dual is doing great for me for now. I am happy till upgrade bug strikes, but otherwise journey with Dual will happily continue . 
 I have the Dual alignment gauge.Norman I'm glad you find your 1229 to your liking.I tried mats,total contact cleanings,many cartridges on mine,the alignment tool to no avail.I have the ability to finely adjust the VTA on my Rega and P+E 2040 which makes a huge difference.I tried it on my Dual but it is basically up or down for a stack of records.I do like the Duals build quality though,I still have my original 1019 and owners manual I bought in the 1960's.