In a front engined FWD car it seems under heavy braking the weight transfer is very apparent where it feels like the back end gets really light. In the MR2 under brakes it feels much more balanced and doesnt have that front end dive like most cars. Of course suspension has a lot to do with this too.

I agree with others who state you need to find out the limit at the track or it could end in tears.
Depending on your set up will govern how you drive the car. Vinny's car was very touchy to drive. You need a lot of finesse to drive it well. If you lift it was facing the other direction before you knew it. I would not drive this car in anger on the street. Why? Just the set up of the springs/dampers plus the age and alignment of the car. Also ran a open diff.
Mine ran spring rates at R8kg/F4kg which made the car dive mid corner causing it to understeer then snap out making it a busy drive. Changed to R8kg/F7kg which settled the car a lot allowing far more control and management of snap oversteer. A lot was gained from shock settings which managed oversteer and settled the rear of the car under load (softer was better) but as others have stated the bias must be correct or it can be a handful.
Incar with 8/7, too much rear bias and a broken rear toe link. It was ok but under hard braking, if you tried to turn in under braking it snapped out.. http://www.youtube.com/watch?v=lhJJ6bcxbNw
Here is Adrian showing how its done in a NA. Nice driving mate. http://www.youtube.com/watch?v=i_Q0abo-iMY
Here is another great driver in a NA managing it quite well. http://www.youtube.com/watch?v=vqOu-EOn3Wc
So as many have stated, alignment, brake bias, also tyre pressures, spring/shock rates, test at the track, watch incar footage and lessons
Good luck mate
 
 

be smooth, brake early (& brake enough), and commit.
 
whether you know it or not with an MR you're committed.... a late change of line or backing off mid corner isn't something they're forgiving of, so you might as well own the situation.

^I'd say a turbo would be a lot more rear weight biased than an N/A.  

I was just taking a punt. I thought I remembered reading 60something / 30something but that was a while ago and I'm probably well off the mark. 56-44 does sound more reasonable. 
 
I don't think the turbo would be too different. All the turbo gear wouldn't weigh too much. But then again I may not be the right person to trust with this kind of info.

^yep I totally forgot about the E153 feels like its made out of lead compared to the S54 + physically bigger. If anyone has taken the stock iron downpipe and Cat and associated brackets off a CT26 they will damn know how heavy it all is!! not to mention all the IC piping as well it all adds up.

I'm by no means an expert, but I did my first track day on the weekend.  I found the best way with my setup  (gen2 turbo running 14psi Willwood front brake upgrade, stock gen2 rear brakes, BC coilovers set to full hardness both front and back, 215mm tyres front and 265mm rear),
was:
 
a sharp stab of the brake to move the car more onto the front wheels just before turning to get extra traction on front.
smooth throttle constant throttle until about 1/2-2/3rds through the corner and apply as much power as the corner dictates coming out.  
 
I found that this when managed with the right amount of throttle was good. I didn't experience any snap oversteer.  I did loose it once, but not in a big way, and didn't spin.
 
I definitely need to upgrade the rear brakes as locking up the front happened a few times, but not the rear (also my rear tyre width would have helped with that).
 
But I do want to re-iterate what others have said.  Go to a track day, try different things. You'll have a blast, and it'll be reasonably safe.  and modifying your car, will modify how it handles.  I personally haven't experienced snap oversteer in my car, I have experienced being fairly sideways, but at no point was it unmanageable.

Your brakes would have been locking due to dampner settings. Too hard will cause the wheels to lock. Softer is better