I have 1988 Subaru Leone/omega seats..
Athu these are from a 4 door, they do release to actually give larger clearance to access the rear than the stock.
They are very near the same height width etc as stock seats...I put one in the drivers just to try for a week or so, with drop seat covers over...one had to look real hard to notice any diiference at all.
To install, I used the stock seat runners, bolted to these 2 5mmx 25mm steel bar across front and back with 12mmx 25mm steel U section blocks on the rear cross....these are then bolted to the orginal seat mounting blocks.
The subaru seats are not fancy, good sideways support, firm and comfortable on long trips...
It takes about 10 mins to change back to orginal seats for a show etc.
The only problems I have is:
1/ the center consol lid closing, my error, I should have mounted the seat maybe 5mm further to the door...to close the lids means a small pull on the seat base for the lid to fully close...no big deal.
2/The rear mount of the seat should have been spaced maybe another 5mm higher...minor comfort issue
Both of these adjustments are simple and minor, the inconvieince is small enough not to warrent doing unless Im bored some time in the next few yrs.
Pics? Sry havnt any, but with a sheepskin covers on my seat to protect them (look good to lol) one doesnt notice any difference, except hugely more comfortable.