exhaust manifold / decat primary

hey all just a quick one im doing some work on the micra end off the month n thinking of playing with the mani / exhaust system im considering getting the full sportex kit for the main piping but has any one ever made a manifold eaither 4-1 or 4-2-1 for the car or moddifed and exsisting one to fit ?? as i refuse to play the extream amount of money for the janspeed manifold !!! as in the end i plan on turboing the car anyways but for a while i wanna run full N/A just with a few more horses under there ! like is it possible to use the exsisting mani and make a "decat section " where the primary would be like a mini 4-1 ????