WTB - Larger side feed injectors- any guidance would also be appreciated

Want to future proof my mr2 1993 turbo.  
 
I dont know alot about the injectors / mr2 turbo. I hear of guys leaning out to get above 250hp on standard injectors (440cc).  I am in the slow process of buying all the bolt on bits to get more out of my 1993 rev2 mr2 turbo. The car has an aftermarket intercooler, 3" exhaust/dump pipe, piggyback unichip ecu, upgraded fuel pump (think its walbro 255), ats straight throttle body inlet, ebc.... just got a bored out fuel rail (-6an 8mm) and looking to future proof my goals of getting above 300rwhp with upgrading fuel injectors.  I dont want to get to a dyno tuner and they tell me I am too lean on running high boost.
 
Any opinions or advice or items for sale, please let me know.

Thanks RHOK, power goals are around or slightly above that.  Is there harm by future proofing and going bigger than whats absolutely needed now?

I am currently making 320rwhp @ 17.6psi on gen 3 540cc injectors. Not sure how much more power they would safely handle. I have the sard 850cc injectors for sale currently that Mobi was using. Heaps of scope for power with these particularly if your running standard internals. They are high impedance versus the low impedance standard units. Not sure how or if the piggy back Ecu will handle this.

You can run top feed, just need to change the fuel rail to suit

My car has an Autronic SM4. My guess is they can run anything. Definitely a good call though Tony. I was worried more about taking the side feeds out and replacing them with top feeds, and space constraints.
 
Because the E85 runs cooler and not as prone to knock as 98 I want reasonably big injectors. I got heaps of turbo and lots more timing to use but no more fuel.
 
Also the biggest side feeds are 850cc but tuner said they are slow (latency wise) and harder for precise control at higher engine speeds.
 
People have pointed me at Racer X fuel rail, ID1300 to ID2000 injectors and bigger intank pump (255). these parts are obvious for change out. Its all the other stuff, AN or speedflow fittings, fuel pressure reg, O2 sensor change out, and the fact I cant identify what gen my engine is (i haven't looked real hard) are all in my headaches. Is there any place in Sydney that stocks Racer X stuff? Has anybody gone full retard on a 3s lately? If so please share some detail on the complete list of things to look out for in an injector upgrade. 
 
Ill take photos and share when I work it all out.....
 
MG
 

ATS Racing are also worth a look. I'll be grabbing their top feed fuel kit soon and that gives you fuel pump, top feed rail, injectors (lots of sizes to pick from), FPR adapter, fuel lines etc. This setup is good for 500+rwhp :)
 
Shoot them an email, they're friendly guys gave me some good advice when I asked.