Who made your 9" setup and how much does it cost? What type of differential do you have in it? Is there a weight difference?
What happened was that on my last 8.8" failure the Wavetrac differential failed.
It was not the gears that failed but their axle retention system consisted of U shaped clips that relied on tension to keep them in place.
When the retainers failed they got into the diff and ring and pinion destroying everything.
To add insult to injury the way it failed didn't allow me to remove the axles which had to be cut out of the housing destroying both the housing and axles too.
If I was building another 8.8" I would have gone back to the Truetrac.
After speaking to Moser who is the distributor of Wavetrac they agreed to replace my 8.8 Wavetrac with a 9" Wavetrac.
94Tbird used the 9" Wavetrac in his 05 without any issues since the 9" is retained by the axle ends.
The Wavetrac also has a lifetime warranty.
Getting back to your question I used a Currie housing, brake brackets, and axles.
I ordered the center section from Moser since the differential was being warrantied.
I bought the old banjo style housing
http://www.currieenterprises.com/cestore/05-07mustang9in.aspx
05 AND UP MUSTANG F9 9" HOUSING
CE-7015 $918.95
05 AND UP MUSTANG PERFORMANCE AXLE PACKAGE WITH ABS RELUCTOR WHEELS
CE-7015A $572.95
'05 AND UP MUSTANG CALIPER BRACKETS FOR STOCK BRAKES
CE-7015B-C $109.95
DRAIN PLUG - 1/2" PIPE THREAD
CE-9027 $17.25
I welded in my own drain plug since I bought my housing from JDM who had it in stock.
http://www.moserengineering.com/aitdownloadablefiles/download/aitfile/aitfile_id/185/
Moser Engineering 9" 3MNW35AN350 +3L Motul Gear 300 oil 75W90 synthetic $1,979 - $1,000 credit.
Some members here have had issues with Moser 9" housings accepting some aftermarket parts which is why I would never use their housings.
http://www.s197forum.com/forum/showpost.php?p=208739&postcount=6
I used my old Powerhouse 4" aluminum driveshaft and had the tube replaced.
The new driveshaft tube is exactly 3" longer and used a conversion U Joint 1330-1350.
I don't know if the new rear end is heavier or lighter but I don't think that there is much of a difference.