@Reddtarga - mine is an early 90 Fat Booster which, according to @5sgte, will take a later 15/16" M/C. 
 
 Yesterday I bled the brakes, and the clutch while I was at it. Some bubbles and both pedals came up a bit which is most welcome. For a minute I thought maybe I don't need a new M/C, but then remembered that the pedal v. slowly depresses over time.
 One thing I want to ask about, is the rear callipers and the handbrake mechanism. I thought the mechanism was self adjusting, and it may be, but I have play. If I leave the handbrake on a click or 2, no effect on the car gently rolling, then 1 pump and the pedal is up much higher, where it should be all the time.
 I greased up that mechanism a few hundred kms ago so I'm not sure what's going on.  
The only thing I can think of is the piston seals have swollen a little (after I used the wrong dot4) and maybe that
is causing the piston (and handbrake mechanism) to retract a little ?? I have new seals coming this week so will revisit the handbrake mechanism.  (Ultimately the wrong dot may have swollen/ruined the MC seals as well).
Front callipers already done.
 
 Oh and I have concerns about the ABS module. I get intermittent pulling under brakes, and maybe I need to investigate that further. It may only when I brake hard and not with normal braking - must verify.
While I am happy to get rid of the ABS, my young son doesn't like the idea. I had some bad experiences with ABS in Falcons mid-90s and the MR2 is 5 yrs older. Does anyone know if the later , presumably better, ABS modules can be fitted to a 90T, now forever known as the "Fat Booster"?
 

The SW20 rear handbrake is self adjusting. Just pump the pedal a few times.
Assuming calipers are OK, if it is not holding the front HB cable may need adjusting.
 
Re ABS:
IMO, would probably not be worth while fitting the later ABS. As well as the ABS unit, you'd need new pipes, ECU, wheel sensors, etc.
 
I have the early ABS connected and have no problems with it for normal street use, however I run stock offset 15 inch wheels with the stock size tyres.
 
Whether to disable it or not?
It would appear that the scary ABS cycling problems people have with that early ABS unit during heavy braking on dry bitumen is more likely to happen on rough surfaces, and would probably be worse with aftermarket large diameter low offset wide wheels fitted along with low profile tyres and excessive positive srub radius. Don't forget that ABS unit was designed for 14 inch wheels with 60 profile tyres.
 
However if I were doing a track day, to avoid any ABS cycling I would probably disable it anyway.
Easy to do, just pull the loom connecting plug then reconnect it again before driving home.
 

Thanks @Reddtarga, I have pumped the pedal with the handbrake on and off, and yet I still find
I get a clear improvement in pedal travel by using the handbrake to put the pads closer to the rotors.
Anyway I'll investigate when the callipers are off next week.
 
re the ABS, yes your advice is sound, but I'm not sure that my unit is not all gummed up, which may cause the pulling. Nor do I know how to tell, but I read in the US, you send it away for pressure cleaning and $$$$ and it comes back working fine. Cause I'm a hundred years old and have ridden motorbikes in the wet for years, and have had some disappointments with early ABS, I'd be happy to run without it. But as you mentioned, I do have wide wheels with wrong offset etc which if changed, might minimise any/all ABS behaviours.

I have no idea about 15/16 only the 7/8 and 1" sorry if I created confusion.

@5sgte - right I missed that. I failed comprehension at school too.
I need to recheck some facts before deciding.
I'd like to go 15/16" but maybe there isn't one for ABS and the Fat Booster.....
 

5SGTE
I went from a late '90 7/8 mc to a 1" (using post 94 calipers) using the stock fat booster. It simply bolted on in my case. But yes, good practice to check clearances.

 
TwoDogs, if a 1" M/C fits a fat booster OK, then a 15/16" M/C should also fit so long as you replace ABS for ABS because I believe all Toyota 4 bolt M/C's have the same mounting, even though they have different bores, but you also need to check the pipe outlets.
 
I know that 1" M/C's were used on mid 90's Landcruisers, 4 Runners, and Supras.
15/16" M/C's only seem to have been used on SW20's, so they can be hard to locate S/H.
Unfortunately if fitting non OEM stuff it ain't easy sometimes.
 

Too late -
 MR2 Damage 1.jpg                
 
 
I knew driving without any brakes was not a good idea.

Ah no! :-(

No brakes could have avoided, maybe F1. Trouble with MR2s is that people don't see you behind other cars.
Car in front of me turned left, so another car, in that street, came out in front of me.
Still drivable.

I hope their insurance is picking up the bill.