Im not sure what ASR is (never heard that one before).

Here is what I think the others are:

GT -- Base model. Probably cloth seats, no sunroof. May have

a manual transmission. Normally aspirated engine (no turbo).

GTAS -- Similar to GLT except it gets the normally aspirated engine

instead of the light pressure turbo engine. (Up thru 96

all GLTs had normally aspirated engine). May have leather,

power seats and other upscale options. This is basically

what a GLT is in the 95 and 96 models. Not sure about the

wheels on this (alloy vs. steel).

GLT -- GTAS with light pressure turbo. Lots of nice upgrades. Alloy

wheels. Leather very common. May have wood dash, etc. 97 was

first year the light pressure turbo was added to the GLT.

Auto tranny only. Very nice model.

T5 -- Hight pressure turbo. Probably loaded with everything except

fog lights and rear spoiler. Wood dash not that common here.

Bigger wheels and tires. Auto or manual transmission.

I may have the GT and GTAS reversed.