Performance quesion: VirtueMart1.1.9 vs 2.0.8

[redtiger]

Hi!guys
I need your help.
I am planning to set up my new site with VirtueMart and Joomla2.5.6
I will add up 20,000 products to my site.

I will use VPS hosting server with RAM 1344MB and bandwidth 1050GB for my site.

I used VirtueMart1.1.9 before but the latest version now is 2.0.8.
I don`t want to make my site slow,take ages to show the contents due to any performance issue.

In my case, should i use v1.1.9 or v2.0.8?
which one has the higher performance within the same server?

Thank you in advance.

[redtiger]

Sorry, i just notice that VirtueMart 1.1.9 is not compatible with Joomla 2.5
So i will like to use joomla 1.5.25
So the question is that which VirtueMart version has higher performance with  joomla1.5.25 installed?