2001 8.1 4l80e hard shift? Possible tune

[The_hoove]

I recently bought a very clean 2001 suburban 2500. 8.1, lifted on. 35s etc.  128,000 miles. I’ve been going through everything. I’ve put about 300 miles on it. The shifts have all felt comfortably firm, firmer than my last shift kitted 4l60e suburban. But not objectionable. Until I did a full throttle run getting on the freeway. 2-3 upshift hit so hard it woke my sleeping 6 year old up in the back seat. I’m kind of leaning toward it’s been tuned. Previous owner did exhaust and at one point had a k&n intake in it. The Speedo has been adjusted for the 35” tires and reads right. He put air bags on it, and towed his trailer a few times a year. There are no trans related codes, but my low end scanners won’t give me trans pressure data. 
      Wondering if it sounds like tune related or if there are other common problems I should be concerned this is a symptom of. 
     Also on a side note, there are extra front O2 sensor bungs before the front cats, both plugged. Are those normal on the 8.1? 
 Thanks