Hello!
i think the owner of this car better knows about it 
i am the one 
Ali....
1st of all....i think since u have'nt used the A/C system from last 4 years.....it time for a GAS refill and whole system servicing.....!
it also depends on the condition of Condensor that either its all right or its fins are blocked......when u open up all...the A/C Servicing guy tells you and u can see your self.....
The 92 JX blower is normal blower not the faster like new cars......but its enough to cool a car in 10mins.......so its fine...just get ur A/C system serviced....it will be good enough.....
well talking about its affect on engine....so as u know...its totally a underpowered car....on 1000cc engine with 1100kgs of body weight.....!and on CNG......its gonna die :P......
i have the same 92 JX but after i found out that all.....i replaced the engine with its same gen 1.5L(1500cc) E15.......now its a good combination.....!
if ur engine is good enough and not worn out.....it will work fine but no pick at all......!
the best place to get ur A/C serviced was one on SHAHRA-e-Faisal where money exchagers are all on service road...its named ICELAND with red board on shop.. its on same service road....
other are on TARIQ ROAD...where all A/C shops are there....named QUICK Cool CENTRE....its from where i get my Sunny A/C Serviced and gas REFILLED.......Ph No is 4538583......they charged me 1600/- for whole service +gas refill...........now its good enough to cool down a car...
For Paint Job.........there are many painters in KHI.......there's one on Tariq road named SHAMSI AUTOS...there a person called TAHIR....he is good in that...ask anyone for that.....!
ANy help needed....i am there.....
THanxxx