The LS350 you have there is a cartridge body on a par with the current Audio Technica AT120, AT440 and AT150 cartridges - it just happens to be the p-mount version of the family.
You can fit the cartridge with authentic audio technica p-mount styli such as:http://www.turntableneedles.com/search. ... &search=GO
Or you can use the styli for the 1/2" mount versions which will also fit:http://www.turntableneedles.com/search. ... &search=GO
Note that the 1/2" mount versions are likely to require an adjustment to the tracking force, but I believe that the TT has a tracking adjustment knob on the back of the arm (at the counterweight).
With the 1/2" styli fitted the cartridge will be a touch heavier and will be tracking a little higher (by about 0.2g) so you may need to get a stylus force gauge or digital scale (I picked my digital scale up for all of $20!) to get a proper measure of your tracking force.
With the proper p-mount styli, the tracking force will automatically be correct at 1.25g (and the styli are designed for an arm of that mass too - so matching is pretty much guaranteed)
The styli do range from very ordinary, to superlatively excellent.... and which stylus you choose can completely transform the cartridge.
I have this cartridge, and fitted with the ATN152LP it is a truly excellent cartridge, competitive with the current AT150MLX, and providing performance on a par with cartridges costing in the 000's of $http://www.stereoneedles.com/audio-technica.html
Shure M92e - cheap, stylus quality relatively ordinary, body is the same as the M97xE except in p-mount version, fitted with the N97xE stylus it gets an instant substantial performance upgrade! - Fitted with a Jico SAS ($180 - not cheap) it becomes a serious high end cartridge - the N97xE and SAS (http://www.turntableneedles.com/JICO-SA ... _3953.html
) are likely to require some adjustment of the tracking force as per the 1/2" Audio Technica styli mentioned above... Although I find the SAS stylus on my Shure P-mount coincidentally ends up spot on... I am not sure whether the N97xE would as well, mostly due to it being a heavier stylus holder. (the SAS is a bit lighter than the Shure OEM)
With the SAS stylus in place this cartridge is competitive with the AT150MLX or Nagaoka MP500 - very serious competition!
Audio Technica AT92E
This cartridge is from the series below the LS350 - a more basic range, of which the AT95 is the 1/2" version (look them up lots of reviews!)
The AT92 is a nice budget cartridge, better in standard form than the M92e (in my opinion) there are also upgrade styli available for it having HyperEliptical, VividLine, Shibata, or Microline needles (ranging from $70 to $150).
At its best with the best stylus options, I do not believe it would match the M92e fitted with the Jico SAS.
Ortofon OMP10/20/30/40 and TM14
This family of Ortofon bodies can be fitted with any member of the OM family of styli.
The OMP20 and up are excellent cartridges, I have both the 20 and 30 - the 30 is noticeably better...
This is an Ortofon OM30 made under another brandname and sold at a cheaper price - you could still pick them up online 6 months ago, but they may all be gone now - and OM30 at less than half the price (I paid $70 for mine, later prices climbed to $150 - still half the price of an OM30)
If you can find one it is an excellent and great value cartridge.
There are other vintage p-mount cartridges like your LS350 which can be found, for which styli are still available - these can often be great value...
The Technics EPC24 as an example - has a laminated core in the body (which improves high frequency performance... and usually only appears on premium cartridges) - the standard needle is OK, but you can fit a Jico SAS to this one too.... the combination is quite high end!
There are Stanton and Pickering P-mount bodies, for which several manufacturers still make needles. (Make sure you purchase from reputable brand as the needle quality does vary!) These can be excellent - and are the traditional competitors to Shure.
There are many more - but it does take some effort hunting them down, researching needles and capabilities, etc...
Hope that Helps