custom carb, air filter and jets

hey guys, I've just recently bought a second hand superbyke rmr 125 and I want to upgrade it and get the best out of it as I can a it's my first bike! I've read up a lot about carbs and air filters and jets and things and I kind of understand the basics of what I need to do but I just need confirmation on a couple of parts and if they would work correctly? toght, so here goes, I haven't got a 150cc big bore kit, but could I still fit this 30mm mikuni carb? ( http://www.ebay.co.uk/itm/400717524504 ) and if so, I'll need a new air filter that's 42mm so this one should be compatible and work right? ( http://www.ebay.co.uk/itm/130727488796 ) and then I can change the main engine jet to 105 which would be this? ( http://m.chinesemotorcyclepartsonlin...o_CRBJT013.php )

i'm a bit of a newbie when it comes to stuff like this so if I've got anything drastically wrong, don't be totally shocked!

thanks!