VPI Classic Cartridge Help


Soon I will be purchasing a VPI Classic and an considering Cart choices. I would like to stick with a $5-700 price range initially. My current rig is a Rega Planar 2 with Ortofon Blue. I purchase a lot of used records at used record stores, thrift stores, etc and wondered about playing these records with a more expensive cartridge. I clean with a VPI RCM but am concerned about beating up a good cart. with "rough" records that have some scratches. Is there any particular cart or stylus type that I should consider? I wanted to order the VPI with the cart installed at the factory and have it checked by the dealer- I think that narrows the choice of cart. manufacturers.

The rest of my system: B&W 802D, Spectron amp, Cary SLP03 Preamp.
stl114_nj
Could someone provide a link to J&R? This is not the first time I've seen them referenced. Looks like they have good prices.

TIA
I prefer a factory mount or a good local dealer to do the work and check the specs for me. That said, I did purchase the DVD from Michael Fremer on turntable setup so I can understand and potentially get involved in changing cart. I would feel the most comfortable starting with the Ortofon Blue for comparison and then moving forward from there once the difference can be heard. But I would lose the advantage/convenience of having a factory mount. Perhaps the dealer would mount the Ortofon for a small fee or free due to the table purchase. As I understand it the Whest can be configured for almost any load but a call to then is necessary for the settings. Generally how are the MM and MC different?
I have excellent results from a used Dynavector Karat D3 Mk II for $300-$400 on my VPI Classic. I love the sound and is a huge bang for the buck cartidge even for the new Mk III $900 if you must have a new one. That will be my next probably or another used one.