Installing bucket seat into sw20

im not sure how, some photos would probably help,
but if you were interested, i would possibly be interested in your recaro seat if you were wanting to part with it,
PM me if you do. with a price

Stock seat rails are useless for aftermarket seats, don't bother.
 
Look for a proper side mount seat rail, bottom mount rail won't work either. Bride make side mount ones, should be more out there too

I have a side mount rail I would be willing to let go for the right price. Shoot me a pm if you're interested

I'm guessing that you're mechanical skill set is better defined as "enthusiastic" than "proficient" - no offense intended.  Getting seats to fit in an MR2 is something of an exercise in compromise.  Most fixed back seats are fairly tall and the biggest problem (please excuse the pun) is managing to include the slide adjuster.  In some cases, depending on your personal height, it ain't gonna happen.
 
Here's where you fall foul of Mr Plod.  Seats are either required to have sliding adjustment, or you need to get the mounts engineered.  Depending on the workshop you choose for that this can be quite a painful process.  I have "heard" of people who did away with the slider, set the seat up to suit themselves, then made sure the mounts were covered over, on the basis that your average policeman would be unaware of what is standard or not.  Not that I'm recommending that you do this, that would be irresponsible of me.  Wouldn't it.
 
Seriously, unless you find an eBay bargain fitting this seat legally isn't going to be a simple cheap project.  Without seeing photo's of just where it won't line up I can't make suggestions as to what needs to be done.  Is the side mount plate too short to cover all of the drillings in the recaro slider?  Are they too narrow to sit on top of the sliders? (Actually, this could be as easy as turning the plates around and having the "wings" come outwards instead of inwards under the seat)
 
Give us some more info, pictures, drawings, whatever, and we'll try to help.

Just make sure when you buy side mount rails that the width is the same as the seats.
 
If you were to use the Recaro rails there is nothing wrong with drilling holes in the L bracket that came with the seat to line up with the rails and using washers to bolt it together.
 
And technically any aftermarket seat should be engineered