Brand doesn't have a whole lot to do with quitening down the exhaust. Get what ever brand you like just make sure you get an offset-offset or centre-offset. Its the offsetting that will remove most of the noise form a 1J. Past that its internal design, If you can a straight through offset-offset glass packed muffler will give you low noise and power.
It is EXTREMELY possible to have a zero loss exhaust that is also quite, its just with smart choices. If I were you I would make a 3" fit, there are alot of brands out there, there should be one that has a low barrel hight to fit with your tight clearences. If not, you only need two extra cuts and welds to angle the system down slightly to make extra room. The shop saying it wont fit is them just being lazy
OH I previously had the Blitz NUR I have just pulled it for a system I built. For those interested the power difference between having the silencer in and no silencer was 45rwkw! thats 60rwhp on a back to back run on a dyno. Lesson? if you don't want a load exhaust make a good flowing quite one, DON'T run a loud one with a silencer
PS my blitz is currently for sale for those of you in Australia!