To clear doubts, just plunk in another HU which perform well in another vehicle at the same location & compare performances when installed in your car. After that make your presumption from the results, wiring or HU. Any well installed antenna within KL/PJ should give you reasonably good audible performances. Btw most Pioneer HU have better clarity compare to others within its price range.

Pros & cons of FM reception; if it's a ori factory fitted internal antenna than memang 'chun' for both Japanese or German vehicles. Our local assy fittings even as advertise using using German or Japanese technology all sucks due also to the cmpetitive selling price. Best value & quality reception for aftermarket installation is no other than the old fashion motorised vertical ones(Harada Japanese brand). Past experience from the German cars OEM internal antenna even from the early 90" have shown to be done with alot of R&D incorporated to the rear & front glass together using multiple digital-pulse signal boosters providing 'Umbrella' coverage. Later systems incorporated with the visible rear roof 'Dorsal' & quarter-glass further improve the 'Umbrella' concept reception. Of course all this R&D cost were also added into the actual factory price of the car which may to about $2K for each car; if one these marques cost in excess of $400K than no problem-lah. Nothing like those ppl who install 'Brothers' cap-ayam 'Dorsal' antenna expecting to get those performance.

Check your antenna installation again, since your car is an imported Japanese vehicle there's a possibility a Malaysia spec frequency modulator has been installed for the previous standard HU. If you have changed to another aftermarket HU & your antenna wirings got no problem, than it's best you install one of those motorised vertical type which I think do not cost that much if you do not mind the asthetic point of view.

Alpine radio for this model have been having bad reviews for quite some time now; not much can be done other than replacing your antenna with original Japanese made like 'Harada' directly plug to HU by-passing all OEM wirings. Installation of the old-skol 'Harada' vertical auto-antenna have solve most of the radio problems for Alpine if you do not mind the asthetic looks.

No difference for radio performance betwen single or double din models from each brands. From most that I've noticed for bad radio reception cases were corrected from re-wiring works & replacement of antenna to at least imported Japanese brands. I doubt German made ones are feasible for our cost-consious market in Malaysia, but as a $ to $ comparision there are values to these type of products which looks similar asthetically but end-product reception quality defers by a mile.

It's just simply replacing your existing antenna with a 'Harada' Japanese motorised vertical antenna & ensure the signal wirings all the way to the HU is properly insulated. Signal can still be enhance further with additional in-line FM Booster if signals are still not encouraging.

I don't have any price as I'm not a trader but a ICE enthusiast. If you're interested you can always PM me your contact number & I'll solve your radio problem if you have the patience.