Speaking as one who's played a leopard shapeshifter - three, actually* - I have this to say: adept for combat, mage for stealth.
If you want to build a combat-heavy character, make her an adept; most of the abilities will translate directly to your shapeshifter form. Find ways to increase your speed (both number of actions and pure ground speed), your stealth (just in case), and your dodge. Remember that without active spellcasting magic, 'can't find' and 'GTFO' will be your best friend.
If you want to build a stealth-heavy character, go with a mage - presumably a Jaguar shaman, yes? Go for illusions, invisibility, masking, some healing - such as Alleviate Allergy - and one mana-based go-for-broke, one-shot kill spell, i.e. manabolt. (If you need to kill a mage, that's claws & jaws work.) I would strongly recommend the two insta-change spells, however - Fashion and Makeover, with which you can be a Diva About Town, go around the corner, and a minute later be Bag Lady From Hell. For you, I'd also at least recommend Catfall.
In all cases, remember that Jaguar and Leopard are stalkers/lurkers/pouncers, not chase-down-and-kill hunters. Lie in wait, or get the drop on your target. Don't play with your food. One hit one kill. Hit and fade. Don't be seen. Remember you are not the most dangerous thing out there any more. Dive for cover, vacate, circle around, and dispose of your opponents.
Good advice for any shadowrunner, but especially appropriate for a jaguar shapeshifter.
* - Who were, now that I think about it, a Duke and Duchess in Tir Tairngire by the time we were done. He was a mage, she had no active magic. Their cub was a phyad.
