Will I notice a big difference between the header I have now (heddman chikara torque-step 4-2-1 two piece) and a dc 4-1 stainless header. Also, what is the difference between a dc header and a dc jdm header?

 

the difference is in design. dc and dc jdm versions have differently sized collectors. dc jdm is 2.5".

 

I have that DC stainless 4-1 header ... its sweet ... way quality material ... and I put it on when i still had stock exhaust ... and with a quite exhaust ... you could hear the air rushing through the pipes ... soundzz way spiff

umm as far as 4-2-1 vs 4-1 if your gonna heavily modify the engine .... get the 4-1 ... if not ... if you preffer to race at high speeds ..highway ect... 4-1 ... if you primarily gonna be doin stop light racing ...4-2-1 makes more sense if your not doin much more than I/H/E ...

and as far as 2 piece vs 1 well .... with 2 pieces you got one more spot that it can corrode...leak .. ect... i dunno ... 1 piece you have to take the whole thing out if you ever need to change/move it .... hmmm IF you are driving with a WAYYYY crucial drop ... might want to get the 2 piece for repair purposes (; i perfer 1piece tho

 

get a carsound 2.5" cat to complement your dc JDM 4 to 1.