Many questions about parts I am interested in ordering

First, I have several questions about the Kubler cylinder kit (278 cc).  I have an Aprilia Atlantic 200.  The description of this kit says that it is not a plug and play kind of upgrade.  I am not so concerned about the skill needed since my friend who will be doing the work on this kit is a motorcycle mechanic by trade.  However, I am concerned about the fact that it says that a  primary fixed sheave is needed from a 125 cc Leader engine.  These engines are not so very common in the US (not many 200cc engines either, or I would not need to order parts for my scooter and have to have them shipped across the ocean).  I searched the website to see if I could find the part mentioned (from the 125) but I got nothing from the search.  Do you carry the 125cc primary fixed sheave so I can install the kit on my 200? 
Also, will I need to buy a gasket set in order to install this kit or are all of the gaskets included?
I probably have more questions about the cylinder kit, but they can wait until I know that I can install it on my scooter.
The next part that I have some questions about actually fits into the issues of the cylinder kit.  I would like to install the HiT Dr Pulley clutch on my scooter.  The one listed for the AA200 has a part number of  HIT201203.   However, the description for that part says it fits Leader engines 125, 250, and 300.  Does it also fit the AA200?  I mean a natural, quality fit?  If so, since it fits the 125, would it work with the Kubler cylinder kit without making any changes to the clutch.  (I am assuming that the clutch replacement includes the primary fixed sleave since that is considered part of the clutch.
Related to the clutch, I have a question about the Torsion controller MALOSSI, part number M2513210.  Would this part work with a clutch other than a Malossi clutch, such as the Dr Pulley?  Or would it even be necessary for the HiT clutch?
And just to make sure, the belt ( part number PI833578 ) is an OEM part for the AA200?
IF I can actually apply all of these upgrades to my scooter as well as Molossi and Paloni primary and secondary gear kits, I obviously would also be interested in the Dr Pulley slide weights.  It would probably be helpful to know that my goals are for greater efficiency, not for racing.  Presently, my scooter is most efficient at 45 - 50 mph.  I would like it to be its most efficient at highway speeds (around 70 mph) and still have some acceleration at that speed if needed for safety purposes.  That is my ideal.  Given that ideal, what would be the best weight or combination of weights to use to get the closest I can get to my ideal?  I think 10.5 grams is OEM, but since I am looking to essentially change the whole power train of the scooter, I would imagine the weight would need to change as well.
Well, that is enough for now.  It will get me started so I can know what kind of decisions I will have to make.
Thanks for your help.

Martin, thank you very much for your informative reply.  I had about given up on getting a reply since I checked back every day after posting for about 10 days, but had no reply. 

I need a little clarification on the primary fixed sheave.  Isn't it part of the clutch?  If so, will the replacement part that you mentioned be necessary if I switch to the HiT clutch?  I had gotten an email response regarding this question that said that I would have to obstruct the primary fixed sheave on the HiT.  I am not real sure what that means.  How is it obstructed?  Or, would it be better to be replaced with the replacement you have suggested?  Will the replacement fit the HiT without fabrication?

Btw, I am having to cut some "desires" out in order to keep the cost within budget.  If I was going to change the variator, I would go with the Costa variator.  But I have had to choose to go with the Pulley clutch and weights instead.  Based on my goals, not only does it fit my budget better, but from what I have been able to glean from blogs, and other information both on the internet and from my mechanic, it may meet my goals better.  I was not going to change the clutch, but it has been shown that the clutch greatly helps the Pulley weights and they work together for good effect.

Regarding the weights, 14 is the original weight?  Hmmm.   That is heavier than I thought.  I thought I had looked that up on the Aprilia website. 

What is your recommendation for the best drive belt to use and why?  I don't have much experience with this, have only used OEM belts.  But some say the Kevlar belts are the way to go because they reduce stretching, but others say that stretching is not that much of a problem and that the OEM belts last longer than the OEM belts.  What is your take?

I am going to be putting on a Leo Vince exhaust, what would be the best choice for air intake?  I was considering the XSH tuning airfilter, but I am unfamiliar with it.  What is your recommendation?

Okay, I'll try to answer in short:

1) The primary fixed sheave you'll need is art no C8208 or KBR10004 (reinforced version).

2) All the gaskets are included in delivery with the KÜBLER kit.

3) I'd recommend using the MALOSSI Delta Clutch for your Atlantic 200, art no M5211821.

4) The torsion controller works perfectly with both the HIT and the MALOSSI clutch.

5) The belt PI833578 is no OEM part, we have removed the PIAGGIO logo so as not to confuse the customer there.

6) For the correct roller weights we cannot give you a weight that will definitely fit your scooter set-up. You'll have to experiment a little here. 14g should be the weight provided with the Multivar. Just order some additional weights to see which will suit your set-up best.

7) As you are about to change the cylinder and the clutch, we definitely recommend mounting a MALOSSI Multivar as well. The art no is M5111885.

8) We also recommend purchasing art no KBR10003 for the KÜBLER kit. See item description for information on what this item is all about.