your elevated creatinine numbers are due to your workouts. the amount of creatinine due to creatine supplementation is negligible compared to what is created by your muscles during intense exercise.
there are published studies that show buffered creatine forms creatinine more readily than plain old creatine monohydrate. please don't post BS scare mongering that is used to sell overpriced creatine.
while is disagree with your science in your post, i cannot disagree with your subjective results. my feeling is you could have gotten the same results with creatine, beta alanine and citruline malate. i really think it is the beta alanine and citruline malate that is responsible for the performance increase.
they are the only compounds that could account for it and are backed ever growing consensus, both scientific and anecdotal.
if you want the same thing your friend swears by without the extra crap in it, i would get beta alanine (if price is an issue, it is available in powder form) and perhaps citruline malate.
that along with your cheap creatine will allow you to replicate the components at a lower price or you can get more beta alanine and citruline malate for the same price and reap the benefits of compounds that work ridiculously well.