Summary
1)panel filter £35 token benefit
2)matched inlets £dependant on company but £ for £ the most effective mod you can do to the 172/182. Usually £150, 7bhp ish
3)182 manifold on 172? dont bother £££££ benefits unproven
4)decat £150 fitted, worthwhile midrange torque increase
5)cat back, a proper one teamed with a map can see good gains, but to me its more about the noise! worth doing as the standard renault pos will fall off in the next 5mins anyway
6)remap 100% yes, around £350 but think make sure you do it last, tuning is addictive and before long you will want CAMS!!!!!!!
which are next....