I mounted my Alpine mrp m850 under the spare tire. its been going strong for over a year. I also have the sliding floor so it made my install even harder. but the spare tire fits in just the same and my amp has not overheated yet. this includes 5 and 6 hour drives to sc and NJ. I just pushed the amp as far as I could towards the front of the vehicle and dropped the spare tire over it. The tire sits a little bit crooked but once i put the put the removable black cover on its in there and everything opens and closes correctly. Those alpine Mrp m series amps were made well. I never seen a post about them getting hot.

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E53 06 3.0i

wishlist
Comfort Seats
speckdock 2.5

Mods
Air suspension - wip
skid plate replica - in box
OEM sunroof deflector
OEM bluetooth streaming
navi,dsp,tv retrofit - wip
Low prof roof racks
2 directtv satelite tuners
Grom audio usb2
quarter and back window sunshades
2 10"subs- boxes opposite sides/Alp MRP-M850
rear heated seats retrofit
rear footwell lights retrofit
remote window roll up