Adding 2 channel goodness to existing reciever

I have Marantz SR7005 which has preamp out. I am planning to go with Vandersteen 2Ce Sig II or Treo along with Vandersteen VCC-5 . I preferably want to keep using existing Marantz so that I can use it for my 5.1 HT.

How do I do this?. Can I just bypass the 2 channel out of Marantz and just add new amp for both the channels?. Or I have to go with a new preamp with HT bypass and connect the CD/DAC to the preamp?.

I am planning to start with Rogue Audio/Prima Luna/Emotiva/Cary Audio/Pass Labs etc. Can I go with amp that can put out more than 160 watts per channel?. I was wondering if that can damage the speakers?.

I also want to try out Vinly in a year or two without have to change the amp.

Any advice is appreciated.
1. You can do either. Just adding the amp will give you the quality power to drive better speakers. Adding a good preamp with "HT Bypass" and a good phono stage will give you a separate stereo system with the ability to still use the AVR. Look at the new Parasound P5 for this application.

2. You cannot have too much power unless you use it irresponsibly.
Keep your front three channels with the same power. Save some money and buy a 3 channel amp. Use the Marantz for the rears.
The Marantz should have fairly nice quality sound. Does it have a "direct" mode?
The problem Marantz has is that it is very poor in creating a deep stage. Wenn you would buy a poweramp which can build a deep and wide stage the Marantz will f... it up. I have done these tests so many times. Wenn you have an Onkyo and you will use an amp which can give a wide and deep stage it will work. It depends about the properties of the amp.
Hi Bo1972,

Why would Marantz f... it up when preamp and 2 channel amp takes over?.
Because it has not the property to give depth. Vandersteen speakers can give depth. So you need an amp who can do this. Wenn you put an amp who can give a deep stage on a pre amp who can't give a deep stage. It is al gone. It is that simple!
Keep your front three channels with the same power.
Excellent recommendation. To go even further, the center speaker needs to be as good as your mains speakers, particularly when you select Dolby surround.

All my 3 channels have the same monoblocks and the speakers are the same brand with the same drivers in a smaller cabinet.

In fact, all channels have the same amplification and speakers. The sound is terrific and it is something worth considering.