No, to the question in the body of your post. Yes, to the question in your title. Your augmented maximum for an attribute is +4, as detailed in Step Six: Spend Your Resources in the Creating a Shadowrunner chapter of the corebook (for me, that's page 94, but I understand that pagination is different in different printings and PDF releases).
All sources of bonuses to your Attributes stack together unless they specifically say otherwise, but the total bonus is still limited to your augmented maximum of +4. If you have +1 Agility from cyberware, +2 from Improved Physical Attribute (Agility), and a +1 from a friendly mage casting Increase (Agility) on you, you're maxed on Agility buffs. If you get another point from cyber or adept powers, you can do without the spell buff. Regardless, the most you can get is +4 over your current (natural) max, except in one situation...
Full cyberlimb replacements actually replace some of your physical stats, rather than modify them. They count as your "natural" attributes when using those limbs. However, you can only get those made up to the same as your racial maximum anyway, so the highest you'll EVER have any of your attributes is still your racial maximum +4, whether you hit the max spending Resources (and Essence) or Karma. (Don't forget one attribute can go one point higher with a particular Merit!)
There is one other set of "Attributes" that can be raised higher, in a manner of speaking. The Technomancers have access to a Complex Form that increases Matrix Attributes, and that Complex Form has a unique maximum of "double natural Attribute" rather than "natural Attribute + 4". For deckers, their Matrix Attributes are based on their equipment, not their stats, but for a Technomancer, that's the virtual equivalent of allowing double, say, Charisma instead of Charisma + 4 as their attack stat. Even more wrong, the way most people I know read it, you can get the magical/cyber +4 to your "real" Attribute to raise the corresponding Matrix Attribute by four, THEN double the boosted Matrix stat. So, Elvish Technomancers with friendly magi and a serious dedication could get a 26 base Matrix Attack stat. Have fun with that.