Hi Tidal. Can I first say that you need to find a dealer that will let you listen at home because you need to trust your own ears. Only you can decide what you like best. Anyway, here's my thoughts on your post.
Tidal wrote: I can understand that RP3 plus TTPSU should be sonically equal to stock RP6.
I wouldn't say equal but very close. After all the only difference between the two is the platter.
Tidal wrote:1.Rega RP3 with Elys2, may be coupled with TTPSU - $900 + Unknown TTPSU price
2.Rega RP6 with Elys2 (the only reason I prefer 6 rather than 3 now is that 6 looks very sexy!) - $1,600 (this choice forces me to lessen the phono priority)
3.Clearaudio Concept MM package - $1,450 (most appropriate in the range, higher performance but also encircled by rumors of building quality and after service care)
4.Pro-ject 2 Xperience Classic - $1,600 (this price doesn't include cartridge, so quite impossible..)
OK, lets start with the Clearaudio. They are very well put together (much better than Pro-ject or Rega) and they look good too. Before I started listening to decks a Clearaudio in the £2000 to £2500 bracket was my first choice. I took one home and loved the look and the build. Sound was good too but somehow it didn't provide what I was looking for.
I am not a fan of Pro-ject and would suggest you take a look at the Pro-ject section of this forum.
The RP3 v RP6 thread should provide you with most of the information on the Rega. Both are good decks out of the box and you can upgrade them as funds allow. But if buying the RP3 I would recommend buying it with a TT PSU and a white belt which will give performance levels about that of the RP6 for less money and provide the type of speed stability needed when listening to classical music.
I agree with nabil regarding Rega cartridges. The Elys2 is OK but not great and I replaced mine with an SAE 1000Lt within a month of getting my RP3.
I have a very wide taste in music and have a substantial collection of classical. I love the piano and in particular piano concertos. I find that DG and EMI recordings work particularly well in my set-up.
My main genre is classical, mainly focusing on concertos, sonatas and quartets.