I realize this topic as probably been covered more than once on this board, but here I go anyhow! I still have the stock exhaust on my 87 K5. Am looking to upgrade a bit. Dont want to spend too much money on this, but will probably take it to a shop to have it done. I would like to get a new catalytic converter (original one still one vehicle). First off, what cat do you all recommend and who has the best price? I want to go with a cat back system, preferbly flowmaster muffler. Which flowmaster do you all recommend ( I have been thinking either 40 series or 50 series) If I understand the 40 series is louder than the 50 series. Which do you all run and recommend? Lastly, if I end up buying this system thru mailorder (only if significanly cheaper than my local shop), do you think they will frown if I ask them to install since I did not buy the system thru them? Oh, one more thing. What do you think it should cost me for a new high flow cat and flowmaster catback system (installed). THanks for your advice.