What RC experience do you have? I enjoy both. The GLR would be easier to setup and get up to speed. Smaller track, or lower traction would favor the GLA. If you have a lot of touring car experience, you may prefer the GLA. If you have pan car experience, you would prefer the GLR.
With the GLA, on a large track you will be fighting traction roll a lot more than you would on the GLR. I am more of a 2wd pilot than an AWD one, so my bias would go towards the 2wd chassis. My finished GLA is 90mm, and it is the fastest 90mm chassis that I own (I have 4 90mm cars currently). If the circuit has high flow, then the 2wd car will perform better. If there are a lot of slower corners, then the favor would go to the AWD in my opinion.
thanks Emu you have been very clear. I have always practiced touring 1/10 but I realized that on rcp it seems to be better GLA