I saw an mx3 for 300.00 GS model says needs new motor. Is it worth it? Best place to find a replacement motor? BTW, I do have some experience behind the wrench just not with Mazda.

 

Very possibly, and depending on your available time, budget, talent and what you want to do with her.
$300 for any car is a pretty good deal these days.

 

Any good places to find a replacement motor? Besides ebay.

 

I think I might be interested in the 2.5L upgrade. Will my tranny bolt up to it? Any problems or tricks I should know? How much should this conversion probably run?

 

No, I'm pretty sure (further research needed here) that the trannys would be different also.
As far as an engine is concerned... they are not the easiest to find (see: Chevy small block) but I have seen them around before. If I have seen them w/no real reason to look, they must be out there.
What about your local bone-yard? Do a Craig's list search. As mentioned, eBay Motors, various forums WTB, Google, Yahoo. There may even be a MX3/6 club forum that may be able to help you further?

 

hey tthere buddy i have a 94 mx-3 that i got for 200 dollars and it had the four cylinder in it when i got it and i put the 2.5 v6 out of a probe gt. It is a task to install but well worth it and if u have a v6 model mx-3 than it is a dirct bolt in. The trans on the four cylinder willnot work on the v6 but the the v6 in a mx3 is the same as the trans in the 2.5 gt. and the 2.5 gt motor is the samw as the 1.8 in the mx3 but it is a smaller cylinder bore size but it is worth it, if you have any other questions just ask good luck