[Sony Xperia S, Acro S, Ion] MarkMRL:
I found how to make the game look decent on our device. It doesn't run very fluid though, especially in some tracks, but the game is playable, and it could be made more fluid with further optimizations, I think (I don't have enough time to test all options and see if they do make a difference).

Basically, all you need to do is open the patch.1041.com.gameloft.android.ANMP.GloftA7HM.obb with Winrar or 7Zip (you can also rename the file to zip and then open it), then navigate to the deviceconfig folder, inside there will be an .xml file. If you don't have the patch file for whatever reason, you need to change it inside the main. file.

Open in in Notepad++ or similar, and you'll see something like this repeated a few times for different devices (such as medium, high, low, etc).

<device name="medium" parent="default">
<attributes>
SOME STUFF HERE
</attributes>
</device>

Well, you need to copy the next part inside all of those blocks. I don't know which one is used by our device, so just put it in all of them (just the first 6 actually). If you feel like wasting some time, you could try changing one at a time and test it everytime until you find out which one is used by our device. Here's the block of code to put between the <attributes> tag

<int name="menu_car_lod" value="3" />
<int name="gameplay_car_lod" value="3" />
<bool name="use_msaa" value="false" />
<bool name="use_hires_map" value="true" />
<bool name="use_render_target_aa" value="false" />
<bool name="use_blur_on_impact" value="false" />
<bool name="use_car_shadow" value="true" />
<bool name="use_radial_blur_on_nitro" value="false" />
<bool name="use_menu_high_res_texture" value="true" />
<bool name="use_orientation_locked" value="false" />
<bool name="use_hud_low_res_texture"	value="false" />
<bool name="use_traffic_shadow" value="false" />
<bool name="use_set_min_filter_linear" value="true" />
<bool name="use_swf_posteffect_render_texture" value="true" />
<bool name="is_low_res_platform" value="false" />
<bool name="use_lodev_textures"	value="false" />
<bool name="use_glLive_iPad" value="false" />
<float name="a_lod_table_box" value="27500000.0" />
<float name="a_lod_table_low" value="15000000.0" />
<float name="a_pickup_visibility_multiplier" value="1.0" />
<string name="showTrackLowLODDistance"	value="FAR"	/>
<bool name="use_gamma_luminance"	value="false"	/>
<bool name="use_second_render_target"	value="false"	/>
<float name="ReflectionMapU"	value="0.46875"	/><!-- Dynamic Reflection Shader U coordinate to take for the relfection -->
<float name="ReflectionMapV"	value="0.3125"	/><!-- Dynamic Reflection Shader V coordinate to take for the relfection -->
<bool name="use_high_quality_car_shader" value="false" />
<bool name="use_dynamic_reflection_on_cars"	value="true"	/><!-- Special case for low device, ignore on high end one -->
<bool name="optimize_dynamic_reflection"	value="true"	/><!-- Skip one frame on two -->
<bool name="draw_car_reflection_garage"	value="true"	/>

This will enable high res graphics (instead of upscaled disgusting pixelated graphics we are getting, FAR draw distance instead of medium, more shadows, lighting effects (car reflect lights, IE becomes darker in the shadows), and stuff. I disabled the blur effect because they look bad and cause graphical glitches (camera angle wrong after collision when you use the super turbo thingy).

I am pretty sure you could manually do this and make a working XML for every device. Included in my post you find an XML for the latest paid version of the game from Play Store, that you should put inside the patch.[...].obb file.

Remember to choose STORE as compression level when you replace the .xml file inside the .obb.

If you feel like optimizing this, you could try disabling and changing some random stuff until you find a good balance between eye candy and performance.