yah twin turbo's are used where u have multiple throttle bodies and u have a turbo going to 1 particular manifold building up pressure on the those particular cylinders, and not really tricky to tune just have to make sure u have the exact same setup on both turbo's just a double whammy of dense air,

and an intercooler sprayer sprays either CO2 which is liquid nitrogen or N2O (which i personally wouldnt suggest because id be afraid of it getting somewhere it shouldn't and blowing up)which drastically cools the outside of the intercooler decreasing the ambient air tempurature going into ur compression chamber, N2O nitrous oxide which is shot into the intercooler, or shot right b4 the intercooler does the same thing but internally and allows for a very good dispersement of n2o molecules which makes a very good mixture gas with a much higher Oxygen content to increase fuel consumption , of course this (as far as i know) can only be ran with a dry nitrous kit, since gas (absolutely) should not be introduced into an intercooler, so the system does require a fair amount of tuning to avoid detonation under the high compression setup, which would (REALLY) want to go to a lean condition if not properly kept in check

this is a CO2 sprayer
http://www.designengineering.com/cry...r_sprayer.html
or a N2O sprayer
http://www.overboost.com/obs/product...t_name=Nitrous Oxide&sc_id=1&sc_name=

and this is a typical n2o system that u have installed on ur intercooler
http://www.overboost.com/obs/product...t_name=Nitrous Oxide&sc_id=1&sc_name=