1/ go to advance auto and buy the part.
2/ look at it and see if there are any glaring errors.
All well & good, but my local Advance will not have the part "in stock" (I can pretty much guarantee this - it is very rare they have anything to fit a Subaru "in stock") - I would have to order it, pay for it in advance & wait several days for it to come in... and at their price - not a real appealing option - even with coupons...a 30% off coupon still leaves the cost at about $20...and if I should take it back, regardless of the reason, as a "special order" item, I would get hit with a restocking fee...been there, done that. If it was a regular stock item, no problem.
of course, it would be better to compare the dorman to an original subaru part.
If I had the money available, I would order both the Dorman part and the OE Subaru part simply for comparison purposes - but, cash flow is sorely lacking around here...which makes steps/options 3 & 4 of your post a bit of a difficulty as well - I cant spend money I dont have, even if I will later get some of it back. Every penny is pinched until I start working again, and get a few paychecks behind me...soon - very soon!
(cash flow is also the reason for not just getting a decent used, lower mileage tranny to put in the 95)
Right now, I am kind of stuck between a rock and a hard place here, money wise. Every purchase needs to be thoroughly evaluated, all options need to be researched, and every decision carefully weighed. Yes, I "need" to get the parts to do the job right the first time (1000% believer in doing that) but I simply cannot arbitrarily buy stuff and then later return it if I dont need/like it. I just cant. Am I being too "responsible"? maybe...but better that than digging myself a deeper hole I cant get out of later...
What I can do is wait. I start working again on Monday - only part time, but something is better than nothing after nearly 3 years, the pay rate is decent, and it is pretty close to home. The old 90 Legacy DD is still running good, and is as mechanically reliable as ever - the only concern is in how rusty the old girl is getting...I have the feeling one more Wisconsin winter is going to be about all I can safely get out of her before she becomes too structurally compromised - the reason for trying to get a better condition replacement online in the first place...She isnt pretty by any stretch of the imagination, but she does what she is supposed to do.