response wise i can only advise getting a good tune up with a programmable ecu like Hondata. You can also get things like Neptune or so. Don't have experience with the last.
Light flywheel should get your response up a bit.
I would say B18C-R but that breaks the bank atleast a bit :-)
Im running a Toda header. Super clearance and good performance...
Driving a stock B18C-R, Hondata S300, Mugen TL, Mugen airintake and kept up with a K20 swapped EM2 today. So im pretty happy with the setup :-)
The DC2 pipe is much longer. I hoped maybe samco or so made a nice tube for this. I'll try and get a good solution for this. Not that much fan of steel pipes though.
For sale my EK9 ECU its from a 2000 model. Don't need it anymore since i have a B18C-R in there now. With an Hondata.
125 GBP Paypal possible costs for buyer.