1981 cb750k advice for Sprocket and chain replacement & general quesiton('s), Experts please help!

[PRIME]

So I'm currently looking to replace the worn/dirty front & rear sprockets along with the chain on my 1981 CB750K DOHC but I'm having a bit of trouble finding exactly what I want.

Currently the bike has: 18 tooth front sprocket
                                  46 tooth rear sprocket
                                  108 link chain

A majority of my driving will be in city but I'd ideally like a sprocket ratio that gives me the best of both worlds (being acceleration and top speed) and seeing as this is my first CB I'm not sure if the current sprocket ratio is going to give me that. Also I've seen that a lot of people seem to prefer a 530 chain over a 630 chain and I'm not sure which one I currently have on the bike or what the exact difference is between the chains. If I have a 630 chain is it just a matter of me buying a 530 chain? or do other components require replacement aside from the sprockets? Also I've heard that an X ring chain is better than a O ring chain? Any advice would be REALLY appreciated as I'm looking to purchase from Dime City Cycles as they currently have free shipping this weekend!

A second question I have is regarding tuning with the carbs. I recently cleaned/rebuilt my carbs with a general rebuild kit from Dime City Cycles and I just bought a 4-1 Mac exhaust and am looking to install it but I'm wondering if I'm going to have to replace the jet's with something other then what came in the kit. I don't plan on running pods as I want a headache.

Here is the link to the rebuild kit: (k&l kit from Japan): http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-carburetor-parts-honda-cb750f-carburetor-rebuild-kit-18-2554.html)

Thanks !

[TOOLS1]

For what you want, I would recommend an 18 t front sprocket and a 45 t rear with a 530 O-ring chain. Just look for sprockets for a 69-76 CB 750, they are 530 and will go right onto your bike.
TOOLS

[Re-run]

Just to help you out for the future a bit.
A 530 chain will not go on 630 sprockets, or the other way around. The links are different lengths.

x-ring, o-ring, whatever-ring, don't get caught up in the terms. There generally isn't a basic o-ring chain anymore. Companies all have their style of "ring" which is supposedly better than whatever other "ring".
Just worry about the right pitch, i.e. 630, 530; After that, just clean and lube them every so often, and don't forget to adjust them once in a while.

With the 4-1, you MAY need to adjust a bit. Generally, exhaust changes on bikes like these, don't require jetting changes, sometimes they need slight a/f mix tweaks but that's usually it.