There was a guy on this list who put a pair of Garmin 430's in his
C150. In a splurge price to aircraft value ratio, that's got to be the
winner. I used to think this type of thing was nuts until I'd been an
aircraft owner for awhile. There are many reasons why its a good idea
to "splurge" on your plane vs. just buying a plane with what you want
on it...

1) In California, the cost to "flip" your plane is 8-10% the value of
the plane in sale/use tax, so you lose $17,000 on a $170,000 flip
anyway.
2) When you first buy a plane, even a "perfect" plane with a factory
service center inspection, you will spend a lot of money getting it
right for you. You can consider this a purchase cost you will have with
any plane you will buy.
3) Probably the most important thing, your plane is a known quantity.
Most of us are buying planes that are 20 to 30 years old. At that age
there can be a lot of gottchas. The risk of a gottcha with the plane
you know well is less than something you've never seen. There are many
gottchas that don't get caught on even the most complete inspection.

-Robert