S14 SR turbo setup questions

[DJ_Sunrise]

hey everyone, i have an s14 notchback sr in my 95 240 and im trying to hit 300 whp, so i was wondering if anyone had any suggestions? my current setup includes-
-walbro 255 lph fuel pump
-blitz fmic
-MR turbo outlet
-MR downpipe
-Apex'i N1 dual exhaust
-Apex'i PowerFC
-Tomei expreme exhaust manifold
-metal turbo suction pipe

As i was saying, i would like to reach 300 whp. Since my hot pipe has oil leaking into it, im assuming my stock GT28 is on its way out, especially since i only achieve .5 bar of boost, whereas for the last year i was seeing .8ish. I was considering which turbo to swip in as a replacement, within a reasonable price... including the S15 GT28, Garrett 2871r, among other turbos. i use my car predominantly on the street, and dont like to go past 6500 rpm too often. the parts i know i will need.. Injectors, but what size is recommended? 300zx mafs, boost controller, but should i go with manual or electronic, and obviously a new turbo. Any insight?

-Bart