polini 175 vs malossi 172

main difference is the lining, where the malossi item is completly aliminum with a nicosil lining coated thinly onto iot the polini has an 8mm iron sleeve. this means the polini is harder wearing and can be rebored quite a few times. the port map on the polini is rather lazy tho and does need alot of work compaird to the malossi. also the polini needs welding sooner into grinding (the exhaust tract is fairly thin by comparesen) the good points about the polini item are the fact you can use a drop forged piston (harder basicly) rather than a soft cast item, this means its harder to melt holes in your piston and there better suited to forced induction and nitros oxide. malossi is better to bolt on really as theres more power top, polini kits usually make better torque and are desighned so you dont have to rev it like mad to get it moving. polini kit will obviously last longer as you can blow it up and rebore it many times (just need to find the right piston) where as the malossi item is prittymuch scrap if it goes bang. the cooling isnt really affected as the thermostat does all the work there, the polini kit being iron will store heat more sao will open the thermostat earlier buit it wont run any hotter than a malossi. this is a breif look into the diff barrels but like i say both have strong points aswell as bad and its all down to what you want from the bike.