yeh most turbos fitted to cars are made by garret... they have a universal fitting, a t28 flange is a t28 flange just like a t3 is a t3... basically any car that runs a t28 can use a t28 off of another car, like if the meggy runs a normal cored t28 with normal bearings, you could stick a t28r with has a rollerbearing core on it from a nissan s15 silvia, the rollerbearing will make it spin up quicker etc.. then you have the diff ar ratios of the exhaust side, it gets very very confusing, like some people will use a t3 compressor on a t28 exhaust housing... so they can fit it to a t28 manifold lol... its all complicated, there are a few good books on it u can do all sorts like getting cut back blades, then there are diff types of turbo like twinscroll and vnt, a vnt turbo has vanes inside it so at low rpm and low pressure it acts like a small turbo... then at a certain pressure they open up to make it a bigger turbo... its very confusing lol....
have an ask on a meggy site weather its map or afm type sensor and what size turbo then post back would be interesting to know
and also what the spec of the turbo is like the ar ratio and if its a rollerbearing or not...