172 mods should work for the 182.
Same engine realy so 200hp is possible probably easlier than a 172.
Cams, ported head, Unichip (or similar) and Cold air intake should get you some more power.
I know the cams on the 182 are different and I recon there probably less extreme (to help lower the point of max torque) so a change for stronger cams will gain more than a 172 would. Possibly 25hp with a unichip and cams and some intake work.
The 182 exhaust is less restrictive with a freeer flowing race Cat and noiser exhaust.