Hello Eric,
i'm working on an Tamiya A2 at the moment. So i can tell you something about their Abrams kits.
First thing is that the parts fit all together very good (Tamiya like) but the kits also have some inaccuracies like the running gear, smaller details and the missing anti slip coating.
I've managed to apply it with cheap terracotta spray. In my opinion the result is a very good one atlhough the roughness is not the same all over the tank due to some influence factors and testings. It is important to spray several THIN coats from a distance of about at least 30 centimeters until you're happy with the result. Just see my result for yourself:
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http://s1.directupload.net/file/d/2656/w92imkwb_jpg.htmIt is actually a pretty simple kind of work but it requires a lot of masking. It took a lot of masking tape and liquid 'till the job was done...
Let me tell you that you will have to do a lot of work to make the Tamiya Abrams become an all accurate one. Just like the kits from Trumpeter and Italieri it has it's "lights and shadows" with lights to prevail. In the end it turns out in an Abrams-looking model so or so. So it's good for an OOB build. I did only a few additional details so far like some bolt and nuts, some plates and so on. The biggest details which i have added are the anti slip coating and lots of welding seams (had to practice you know...).
So much for the basic kit, let's get back to topic. Yes, the kit is good to represent a late 80's M1A1. You can use chevron tracks. There have been A1s fittet with these, even in the Gulf war if i'm right because the material had to be used although the new T158 BigFoots were already introduced. But i don't know which specific vehicle had which tracks mounted on and when.
I can't help you whit the APU (i'm always confused about it!), the paint and the decals but i guess that there's an expert around here somewhere?