It's right by the bridge so if you drive to fast you might just miss the entrance (first hand experience >.<). The first time I went there I was instructed to park outside the premise and pass the keys to the SA after the security guard ask them to come out. The second and third time I went I terus drive into the premise and park by the side to pass the keys.
The waiting room can look into the hangar (do you call it a hangar if it's for cars?), looks like it can house about 4 cars. You can sit there comfortably sipping your free hot beverage and stale cookies while making the service mechanic uncomfortable as you stare him down. No nasi lemak though

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If you're like me who don't really want to bother someone else to pick you up for 2-3 hours service then drop you back, there are some places to eat/chill nearby but requires a little bit of walking if you don't mind chinese food. If not, the nearest landmarks would be 3rd mile square or scott garden. You can also opt for taxi if you're not the walking type.
My SA is not very informative and doesn't seem to be familiar with Mazdas though, not sure if he is new but I always dealt with him the last few times I was there. When I told him about the kruk kruk ngek ngek he doesn't seem to be aware that this issue is common with most mazda 3s.
The first time I went in for 1k, service all smooth and also the time I asked about the noises. So after 2 weeks my parts arrived and it took 3 hours but at the end of it they told me it didn't fix the problem and asked me to come back again when the other part arrives. Fixed my problem, but didn't fix my nyek nyek problem from wet conditions which I did tell them.
Overall, I would go back again. Nothing unpleasant in particular, nice waiting room.
Thanks for the sharing MissHanz.