The macbook air only allows you to have 2GB of RAM, that sucks when you want to have a bunch of apps open. That is my performance issue with the airs.
MOST people don't use a full 2 GB of RAM. There certainly are some who do use it. I don't see the 1066 MHz RAM as a limitation really, although your rev A has 667 MHz RAM. I would prefer my 2 GB of RAM in MBA over the 4 GB of RAM have in both unibody MB and v2,2 MBP.
Truly, for MOST apps and MOST users 2 GB is sufficient. Those numbers are changing, and I believe the MBA rev C will have 4 GB of RAM standard. It seems pretty obvious what Apple is doing now that it can easily manage 2x2GB chips on the new MBA computers. I believe, I AM NOT POSITIVE, that there are two 1 GB RAM chips soldered on the board. I think I remembered reading that, so seems that with now better pricing and that other high-end Macs are moving to 4 GB the MBA will next. I say high-end as the nicer iMac, MBP, and Mac Pro all have 4 GB of RAM or MORE in the case of the high-end Mac Pro.
I believe Apple will give us 4 GB in the next rev C MBA. However, I will take my 1.86 GHz rev B MBA with SSD and 2 GB 1066 MHz RAM, over my unibody MB 2.4 GHz (I know it has 1066 MHz RAM TOO) with 4 GB RAM, 7200 rpm HDD and my 2.33 GHz MBP with 4 GB 667 MHz RAM and 7200 rpm HDD.
RAM isn't all it's cracked up to be if not fully utilizing it. I find that my MBA definitely does WELL compared to unibody MB and MBP. So, I just don't get this performance issue. Unless you are putting SSD in your MB... and you are going to find a better quality display to somehow add to it as remember you are losing QUALITY and viewing angle capabilities in your MB display. And you are going to swap the CPU for one like the MBA or MBP have with more L2 cache.
Honestly, I don't think you are talking about a performance boost if you were talking a rev B MBA with SSD. BUT, you are talking about a rev A MBA with 2 GB of 667 MHz RAM.
I predict you will be using a MBA rev B or rev C within a year's time, assuming the financial aspects are not the limiting factors. And assuming that this is truly a PERFORMANCE upgrade? And I must assume you will eventually learn that the rev B MBA with SSD does outperform the unibody MB for MOST tasks and common interactions with computer.
Make sure you do some research and are going to be as happy as you think with that MB. It is pretty until you turn it on. Just like the original MBA. LMAO. That will get me some hate mail.
Good luck.