Plinius 8200 or Sim I5?

I owned an I-5 a few years back. One thing to keep in mind when matching it with other gear, is that it can sound lean at times. So I'm not sure what effect this will have on your Dynaudios.

I had an 8200 integrated for a few months 3 years ago when I sold my Aleph 5 & actually having it made me decide to stick with separates. It was powerful but lacked the detail & soundstage (of course) of the Pass I had & the Ayre I went to. As I understand it, these deficiencies have been addressed with newer versions but I can't say that for a fact, as I've not auditioned one since.

I would give the nod to the I-5 for sure, Achou
makes some good points about the quickness and clearity of the unit. It has speed that other amps just can not product.
The sound stage is huge and the imaging is pin oint accurate, Sim gear is known for these traits.
I wouldn't worry about the 70 watts of power, the amount and quality of current the I-5 produces will make up for that and more. I EASILY drove a pair of 1.3se dyn with absolutely no problems.
CR

I haven't heard the Dyns before, but I have heard the Simaudio I5 (with Simaudio Nova and both JMLabs and Paradigm 100v2 speakers) and the Plinius 9200 (with MF Tri-Vista cd and Sonus Faber speakers).

The Plinius had very deep extended bass which sounded over-pronounced and unnatural to my ears. It also managed to muddy all of the mid-range details in orchestral music. But it was very powerful.

The I5's bass does not extend very far, but it is very fast and well-controlled. This lack of bass extension may not be important for your bookshelf speakers. It has extremely good imaging, and it is very resolving. After I put the I5 in my system, I had to put a isolation transformer on my cd player to get rid of high frequency hash that was not audible with my old amplifier. Now I can hear background details like the air conditioning system purring and clicking on 'Mining for Gold' on the Cowboy Junkies 'Trinity Sessions' album. On the 'Misguided Angel' track, I noticed for the first time that there are male backing vocals on the chorus.