My system was custom made for another guy, Daz and installed by Ringwood performance exhaust. Took them about 14 hours or something because its the first they have ever done. Although 2nd time around they may do it faster or at least give a more accurate quote.
As for getting it custom made the car is a bit rare so just about any place in melb would be doing it one off and may not do the best job *shrug* could be a bit hit and miss.
yeah go for a CPE/CS system as it should be a easier for a shop to install - i fitted my downpipe and its a pita but have all the tools if you wanted to attempt yourself.
im running a CS system and it sounds awesome, just need to finish off the second cat section
i would definitely be in for any tuning options in melbourne. also had a quote for tbe with split dump and varex muffler the other day for $1700 full stainless...