Hey HemiDuty,
The ignition advancer was the first mod that i did as the bike already had the jet kit when i bought it, i found that the advancer made the bike rev quicker and more responsive to throttle imput, you don't need to dyno the bike to tune it you just take the standard one off, set the advance of the new one and bolt it up simple as that.
It is a Factory brand ignition advancer cost me $120.00 and should be available at your local bike shop.
I also put a set of NGK CR9EK twin electrode spark plugs in.
FLAT SPOT
I noticed a similar flat spot on my bike but very slight, i got rid of the vacume / pollution module under the airbox and plumbed the carbie float bowl vents to the airbox. This basicly lets the same amount of pressure into the carb float bowls as the airbox, this mod extremely smoothed out the bikes fueling injects more fuel when needed and you can run smaller jets standard ZX7R main jets are 180/190 the dyno jets are 126.
The ram air tubes have these huge bowls attached to them these bowls are for 1 making the ram air induction quieter, slows the velocity of air moving through the pipe, i cut the bowls off and plastic welded plates on the bottom until i finish my carbon ram air tubes.
Check out this link for how to do airbox / carb mod with pics.
http://homepage.ntlworld.com/webzxr/zxr750r/index.html
Go to Tech Tips then Float bowl vent mod in pictures.
While you are there check out Kens tips lots easy mods for a little more HP.
Hope this helps with the flat spot it cured mine.
I can make the exhaust hanger if you require one its made from 4mm aluminium and has holes drilled and countersunk for lightness (and the race look).
Currently fits the standard mounts same as the rear bracket.
You could have any the following finishes.
Plain Aluminium - $45.00 + postage
Aluminium painted Matt black - $50.00 + postage
Aluminium painted Satin black - $50.00 + postage
Polished Aluminium - $60.00 + postage
I can post a pic of the one on my bike but im still finding it a mission to get the photo to a decent size they are currently 466KB i can email one to you if you like.
Hope the info helps.
Cheers,
Matt