Need help in general and for choosing mid ranged amplifier

Hi,
i am new in this question but run a lot of forums and got totally messed up with all the information and would be really happy if You would help me on this.

I currently have used pair of Triangle Celius ESW speakers and 300w Klipsch R-10SW subwoofer.
I am using it in pretty small room, siting position is ~ 2,7-3 m. from speaker. I have used them with used home cinema Pioneer VSX - 821 amplifier which just burned out. Now i am planning to buy stereo amplifier and need help for that.

Specifications of speakers:

Triangle Celius ESW

Bi-wirable
Bass driver Triangle T16 DR110C (x2)
Mid driver Triangle T16 PP122o
Tweeter Triangle TZ202
Sensitivity (dB/W/m) = 92
Freq Response (+- 3Db) = 45Hz-20kHz
Continuous Power = 120 W - at 8 Ohms
Peak Power = 240 W - at 4 Ohms
Nominal Impedance = 8 Ohms
Minimal Impedance = 5 Ohms
Low Frequency Roll Off/Crossover = 400 Hz
High Frequency Roll Off/Crossover = 4 Hz
Dimensions = 44.5 x 8.7 x 11.7 (H x W x D)

QUESTIONS (sry if they are stupid)

First of all i want to ask dumbest question of all:
1. What is mine loudspeaker impedance 8 ohms or 4 ohms - which amplifier I should look in to at first place working with 8 Ohms or 4 Ohms.
    As far as understand my loudspeakers are rated 8 Ohms, but what is confusing they are Bi-wirable (two ,,+" and two ,,-" connection on each of loudspeaker) and i don’t use this I just connect them with metal plug connecting both minuses and pluses like this.

Doesn't that mean that it becomes 4 Ohms (8*8ohms/8*8ohms) ( as on same loudspeaker 2 speakers 8 ohms high speakers + other part of pair 8 Ohms are connected together)? I mean does 8 ohms are rated for whole speaker no mater u are bi wiring or not or not?

2. I have calculated I need somewhere 105-120W RMS power amplifier for channel (in calculators distance from source 3 m, desirable level ~100 dbSPL, speaker sesivity 92 db, amplifier headroom 3 db.

All mid ranged recommend stereos I can find under (500-600 eur.) are with low power output 60-80 W per channel for example Cambridge Audio CXA60. All i could find in this area to fit power needs are: Yamaha A-S701 or Yamaha R-N402D.

2.1 Is this the correct amp. Choice, maybe you can recommend some?

2.2 Do I really need such powerfull amp to power those speakers?

3. I read everywhere that if i use only 2.1 system stereo amplifier is better choice than cinema amplifiers is it really true?

Thanks a lot in advance for you answers