Ummm...not really sure what you are asking here.
You have purchased/traded and got yourself last year's S-Works Tarmac (SL3 = 2011 - SL4 = 2012)?
Great bike, I have one myself. Mine has the threaded BB though, and I run 53-39 Dura Ace cranks. I *think* you can buy adaptors for different cranks to go into different BBs. Why do you want to change from SRAM Red, it is the top of line SRAM component. Or do you just want compact cranks? I don't know much about Campy but I know Super Record is very expensive. Then there is the electronic version EPS, sell your soul to the devil for that! Obviously there are lower spec levels available, not sure what the differences are.
If you want to upgrade other components then as you mentioned wheels are another major one where a performance gain is very noticeable. There are a lot of different wheels on the market as I'm sure you know and you'll need to work out application (usage) before we can give reccomendations, And even then you'll probably get 10 different brands/types reccomended by 10 different people! Do you want clincher or tubular? Racing or training? Shallow or deep or in between? Carbon or alloy? Shimano or Campy? Used or new?
Take into account when upgrading your drivetrain if considering Shimano that 11 speed Dura Ace 9000 is starting to become available now and therefore most of the 10 speed stuff won't be compatible.
If you are considering a different group there is (with Shimano and Campy but not SRAM) the electronic versions to consider vs mechanical. Depends on how much money you have and/or how much you want to spend.
Edit: My transitions - I bought a 2009 Cervelo R3 SL off eBay
with Dura Ace groupset and Mavic Kysyrium ES wheels, used that as my race bike for a couple of years. Nice bike, very light. Geometry was a bit twitchy for me so I started looking around for something a bit more relaxed but still race orientated. Specilaized were having a demo day so I went along and rode a Tarmac and A Roubaix. I wanted them both! the Tarmac seemed to have similar geometry to the Cervelo, was stiff but not as harsh as the Cervelo and not as twitchy. Roubaix was stiff too but somehow soft to ride, absorbed the bumps very well. Ended up settling on the Tarmac (S-Works) but just bought a frame and swapped all the components over and re-sold the Cervelo frame on eBay
. Somewhere along the way I bought a second hand set of Zipp 404 tubular wheels. Had a couple of busted spokes but the wheels were basically sound apart from that once I had the spokes replaced. So the wheels now live on the S-Works. Then I was browsing eBay
one day (as you do...) and I saw a regular non S-Works Tarmac frame for sale in the same colour as the one I had so I bid on that and won it but got touched a bit on the freight (from USA) even though I had emailed the guy before I bid to confirm shipping costs. Anyway, frame arrived and it was a good as the guy had advertised it to be with no defects or scratches so I was happy. I had half an Ultegra 6700 groupset in my garage from various wheeling and dealing over time and after I sourced a few more parts I built the new Tarmac up as a...umm...a second race bike (I already had a training bike). Then after a while my training bike developed a crack in the frame and that was the excuse I needed to make the Tarmac my training bike and ride it pretty much every day. I took the training bike frame (Felt) back to the shop where I had bought it to see about warranty. The manufacturer knocked it back apparantly but the distributor ended up honouring it so in the end (about 3 months later) I got a replacement frame but I haven't bothered to build it back up as I don't really *need* it and it gets expensive maintaining so many bikes. I can't tell much difference between the S-Works and the normal Tarmac. The S-Works is a bit lighter due mostly to carbon wheels and no saddle bag or pump and a few grams difference between DA and Ultegra groups too (both bikes have same handle bars, seat post and seat).