I'd like to know what is a good cheap option for a low-mid boost application for a 2ltr motor. Also one that is easily obtained second hand and easily installed, I'm thinking an internal gated turbo is easier from a custom fabrication point of view. I dont want to spend much and would consider replacing with another second hand turbo rather than rebuild. I've seen wrx ones go cheap on feebay, what about SAAB's or mitsubushi evo's and even the 180-200sx family of turbos.
Happy to receive any advice.

WRX turbos are crap, they are on the small side due to the crappyness of the boxer engine.  Plus they use a odball flange pattern.
 
200sx s14 or S15 turbos would be best.  I think from S14.5 they are ball bearing and an improved overall turbo.  These are Garrett and can be easily hi-flowed or replaced.  These turbos use a common flange.
 
Otherwise a RB20 or RB25 turbo, the RB20's are getting really old though.

S14 or S15 is my vote...ticks all boxes.

Is a new one like this a waste of time? $350 landed seems ok and reasonable finish to it all.....
http://www.ebay.com.au/itm/T04B-0-60A-R-T28-0-86A-R-GT28-TURBO-CHARGER-/220899971362?pt=Motors_Car_Truck_Parts_Accessories&hash=item336eaa1122 
 
or is it better / cheaper to go Secondhand? 
I know if I can get one with all the pipes it will save some fabrication and cost for fittings, 

hi mate a s14/15 is a good idear also look at the chinse way as well very cheap and not to bad as long as the boost is not of the hook...
 
 http://www.ebay.com.au/itm/260881861012?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Well I've been looking and the options are boggling, I'm trying to find a good used t28 of the S15, but even this seems complicated, with lots of variables. Then there is the occasional genuine Garret, GT2860 or 2870, rs and r's and etc.
Even the T25  might be useful, I get the idea it fits in the same spot as a t28 so I could upgrade to a T28 later without reworking things? 
What is a GT SS turbo, is that compatible physically with the T28 and T25?
Is it accurate that a T28 is bushed and a GT28 is ball bearings?
 
Thanks
 

well I dived into it and looked at 2 t28's this arvo, the first was apparently BB but wasn't and was in rough nick, the second one kind of threw, he swore blind it was T28 but it just looked small. turns out its a rb26 turbo, small but hope it will meet my needs. Does anyone know if I go to the effort of custom exhaust flanges can I upgrade to a bigger T28 without mucking around and refabricating?. The one I have is a te2701, ar42...

An rb26 turbo will be on the small side, it is effectively a 1.3L turbo.

Do u kno if it is an r32 gtr turbo or r33 gtr turbo?
I would tru and get a t28 straight up there cheap n will save the mucking around...
Check out nissansilvia.com theres always t28s for sale up there

so what is the go is the te2701 bigger than the stocko t25 or close?