They are no longer in the RMCoM catalogue. Machined Aluminium Specialties made a particularly nice set but I believe they are out of production too. There appears to be a void here in the aftermarket for these wire wheels.
MFH has recently released a set of Borrani rims for those with deep pockets. You could probably pick them up cheaper elsewhere but this link does have a photo http://www.spotmodel.com/product_info.php?products_id=50236
There is also the Model Car Garage tachs though both of these are multi media. http://www.modelcargarage.com/store/pc/viewPrd.asp?idproduct=36&idcategory=10 http://www.modelcargarage.com/store/pc/viewPrd.asp?idproduct=35&idcategory=10
Just be prepared for a long wait when placing an order. My last order was acknowledged as received on 18 June and I'm still waiting. The product is worth waiting for though and as always is above reproach.
Zero paints are another option if airbrushing. Its base coat/ clear coat like Gravity paints and comes in a bigger bottle that works out cheaper. http://www.hobbyworld-usa.com/Store/paints-and-finishes/3264-petty-blue-paint-60ml-.html
That is coming together nicely. EJan make a comprehensive upgrade kit for this Daytona which includes P/E wire wheels with aluminium rims. I believe EJan is actually Model Factory Hiro by another name. http://www.club-barchetta.com/SHOP/E801.html A lot of these Fujimi EM kits are being reissued in new cartoon type boxes and don't carry the price tags demanded for the original EM boxed issue http://www.1999.co.jp/eng/10304490
I can't really add anything to what Doug has just said. Most of the different airbrushes i have here have the needles marked in some way to identify which is which. I do have to look very closely at some of them with my reading glasses to see the markings though.