Thanks guys for all your input; the kit isn't listed in that price guide, maybe because it's still in production. BTW I looked into the current prices: cheapest is TH @37.99, Quantum has it at 46.99 and HOB list all the 1/12 kits at 59.99.
I would tend to agree that this particular kit has not appreciated in value as it is still available new and therefore not in damand.

Here's the story: I was in my favourite LHS (with the wife and sproggs in tow) and while I was there I thought I'd ask about a simple little kit project to keep me occupied till I get back to work in November. There's not a lot in the shop in the way of kits, all ARF's. Anyway, I was offered a Pica 1/12 scale FW190 that the owner said he hadn't gotten around to. Not really my cup to tea as he wanted $72 for it, and I was still thinking about the 4*40 on the shelf at the time.

Just then, my wife appeared from the back of the shop with this old tatty box with the Mustang in it, which she said she had tried to pursuade me to buy before. I also had the choice of two engines, a TT GP07 or a Norvel .074. With the wife's influence, I chose the TT GP07. I was persuaded to buy the kit and engine on the basis that they both added up to less than the cost of the 4*40 kit.

As you might've guessed, usually a Mustang wouldn't be my first choice, I would've preferred something like a Spitfire. But, as you can see the purchase was circumstancial, so I wouldn't have ordered a new one.

In line with the box picture, I also bought some blue and silver Ultracote.

After some research on here last night, I discovered that my choice of engine was off, so I went back this afternoon and swapped it for the Norvel.

So, I have decided to go ahead and build. After a couple of hours of surfing I have settled on an RAF version. No 19 squadron appears to use the blue / silver colour scheme and Major decals have 1/12 scale decal sheets for the British roundels.

As for overpowering it, the original was designed for a Tee-Dee .049 and 2 channel radio; so I think a .25 is a bit of overkill. I even have the original Tatone metal Tee-Dee engine mount that someone must've plonked in there when they first got this kit.

As it turns out, the fuse doublers for the engine bay are missing which gives me the opportunity to make my own and make the engine bay bigger. The Norvel is a bit longer than the old .049. I think a .15 or .25 would just be too big and heavy...