Newish owner here so thanks for your patience. I have a 2007 with the stock Alpine HU and it isn't working that great (CD doesn't work, gives me some random error readings sometimes) so I am looking to replace it. Is swapping just the HU difficult (on a scale of 1-10 how hard)? Is it easier to replace if I stick with an Alpine HU? Can anyone be trusted to put a new HU in (Best buy or do I need to go to a real shop)? Would an installer need to worry about the alarm going off? Suggestions on a new HU that won't break the bank but might allow for future upgrades (like new speakers or a sub)?