depends on what you want from your sw20.
 
the beams box +shipping will set you back approx $700, will cost you about the same to swap it in and your on your way again for under 1.5k
 
if you definitely want/plan to fit a turbo motor eventually, then now is as good a time is any, but you'd need to buy a halfcut so it comes complete with engine, gearbox, wiring, shafts and hubs etc.
 
also, depending on your state laws, you may be restricted to fitting an engine of the same year or newer, so you'll look at a gen3 halfcut which will be 3.5k+, you'll then need to pay someone to do all the mechanical swapping and electrical wiring (you'll no doubt need to modify the wiring on your ems a little to run the turbo motor.) and obv retune,
 
you'd also want to freshen up the motor (timing belt, seals water pump etc)

If a e153 will help you, I've got one here:
 
http://www.gorillaindustr...sw20-mr2-e153-gearbox/

Sorry to go off topic but are the drive shafts for a LSD E153 the same as a no LSD E153?

Nope different part numbers.
The long drivers side non lsd shaft will work in the LSD box.
The short passenger side non lsd shaft will not fit the lsd box. You can either machine it down or buy it new from Toyota.
 
When I upgraded to the LSD E153 I just bought a new passenger side shaft and used the exisiting non lsd shaft  
 

dasic1

Sorry to go off topic but are the drive shafts for a LSD E153 the same as a no LSD E153?

Thanks
I'm thinking of going the other way, LSD to non LSD

Will the E153 gearbox fit into my 1995 mr2 without any problems?

I assume that your car is an NA.
The E153 box is used on turbos, so not suitable for an NA.
If you have an NA motor you would need an S54 box. 
BTW, the BEAMS box referred to earlier is an S54.

just to elaborate, the gear ratios of the turbo E box are longer, not really suited to a 3sge, but it does fit, you just have to also fit the turbo flywheel, clutch, driveshafts and hubs.

I got a mechanic who said to me he will take it out repair and fix it and put it back in for 1500 what do you guys think?

sounds too good to be true. does he know exactly what is wrong with it yet?
 
also, do you know if your current gearbox had the optional LSD? if not i'd highly advise getting that LSD box, it'll cost the same as this "cheap" quote but you'll have an LSD.