Need some 911 advice

74 911 chassis, 94 body, 3.0 engine.  I have had the car 2 years, pretty good luck although drove it sparingly.  Now everthing is wrong and could use some advice.  Smokes terrible, exhaust fell off last time I drove it and I'd greatly appreciate ideas to get it driveable without completely breaking the bank.
 
Are after market exhaust systems available that are worthwhile?  Anything special as it is aircooled? Recommended shops or mechanics/enthusiasts for engine rebuilds in KC area?
 
Thanks for any info you can provide me.

We are in lenexa off 87th and I35.  I am sure we can guide you in the correct direction.