OK frist off eBay parts are not all junk many are of realy good quality and will last a long time that said many are just that junk if your going to buy noname eBay parts buy simple onces like shifters and cold air intakes most sensor are also a good buy... Here are some pros and cons from personal experience

eBay Short Throw Shifters
At $10-15 this is a good one to try its cheap and almost always better than your rotted out stock shifter

PROS
$10-15 bucks HELLO
Lots to pick from
Steel bushings with ball bearings
Little to no slop
Faster shifts
Smaller gear grouping

CONS
The pivot ball may be alittle smaller or bigger than stock
The bushing may not be as wide as stock
1 of 10 may be a weak cast so over time it may bend or brake
May need to drop the exhaust to install
Mounting bolts may need to be replaced
May hit exhaust heat shield

NOTE: Iv got lots of these over the years all have worked fine

eBay Cold Air Intakes
These are pretty good little to no mods needed

PROS
1/4 the cost of a name brand
Piping is mostly the same as name brand
Lots to pick from
More air flow over stock
Clean look

CONS
Comes with cheap air filter
Almost never comes with a mounting braket
Hose clamps are cheap
May not have sensor mounts for your year
May be to long and needs to be trimed

NOTE: Iv got lots of these over the years only 1 has needed the be cut down and 1 for a 00 Corolla did not have the sensor mount if you get one go to the parts store and get a name brand air filter

eBay 4-2-1 Headers
These are a good buy iv never got a bad one and thay always have fit

PROS
1/4 the cost of a name brand
Piping is mostly the same as name brand
More air flow over stock
Clean look

CONS
Dounut gaskit may be cheap
Threads for the down pipe may need cleaned
Most stick out farther than stock manifold
Some years may not work with your car because of the flanges

NOTE: These work good but on some years the flange to the cat. are set different

eBay Off Road Cats & Test Pipes
These are a good buy

PROS
These flow a lot of air over the stock cat

CONS
Are NOT street legal hope you dont get pulled over and checked
Loud exhaust
Some years may not work with your car because of the flanges

NOTE: These work good but on some years the flange to the cat. are set different

eBay 2.25" & 2.5" Exhaust
These are good little to no mods needed

PROS
1/4 to 1/2 the cost of a name brand
Piping is mostly the same as name brand
More air flow over stock
Lots to pick from
Mean sound
Clean look

CONS
Mounting hooks may need to be moved
May hang low and skrape road
Loud exhaust
May need to buy other gaskits or seals

NOTE: Iv got lots of these over the years most fit good others well fight but worth it

eBay Intake Manifolds
DO NOT GET A NONAME EBAY INTAKE MANIFOLD!!! These are very hard to get to work you well need lots of tools and time but in can be done

PROS
1/4 to 1/2 the cost of a name brand
More air flow over stock

CONS
These are cheap made fast with little quality
May hit other parts in your engine bay
May leak air making your motor run like crap
May need to tap holes for screws
May need to drill holes
May need to grind welds
May not have all the vacuum ports you need

NOTE: I got one of these to save some green... Dont do it to make mine work I had the grind welds around the mounting flange just to put the bolts on the flange for the T.Body was miss punched so I had to drill it out I had to get a vacuum block to run all the lines and it hit the master cylinder WTF

eBay Side Mirrors
These are good little to no mods needed

PROS
Cheap
Looks good
Lots to pick from

CONS
May not be 100% fit
Mirrors may not ajust all the way
Will need the wire power mirrors
May need to reuse old hardware

NOTE: These work good but may not be happy with the mirror part of the mirrors

eBay Head Lights & Tail Lights
These are good little to no mods needed

PROS
Cheap
Looks good
Lots to pick from

CONS
May not be 100% fit
May need to rewire
May need to reuse old hardware
May let water in and burn out bulbs
May fog up for a week after rain

NOTE: These work good but may want to stick with stock lights

eBay Radiators
These are good but some fit better than others

PROS
Can handle more power
Looks cool
Keeps motor cooler

CONS
May not be 100% fit
May need to cut or bend mounts
May hit hood

NOTE: Iv had 2or3 most fit ok but others may need heavy mods to mounts to get to fit

eBay Steering Wheels & Hubs
These work but look very cheap

PROS
Cheap
Lots to pick from

CONS
Most look cheap
Horn may not work
Hub my not fit the 12-o-clock 100%

NOTE: Iv never got the horn butten to work on one

eBay Fuel Rails
These are good but some fit better than others

PROS
More fuel
Looks good

CONS
Bolky/Over Sized
Thredes may leak
May not have all parts

NOTE: Buy thred tape and rap the thredes good before install

eBay Strut Tower Brases
DO NOT WASTE YOUR TIME the noname eBay and APC with the screw on ends are a joke dont buy one

PROS
Ya Right

CONS
Looks cheap
May haft to screw the ends out so far they are bearly even on
No real saport

NOTE: SEE ABOVE

eBay Glow Gauges
These are good some mods may be needed

PROS
Cheap
Lots to pick from
Looks cool if done right

CONS
Will need to cut or drill gauge housing to run wires
Will need to take half your dash out
May come with a cheap wiring kit

NOTE: These may be cheap but they are a pain to put in. You should use a DC volt metter and wire to the factory dash light power swich

quite a write up there sir! i agree that some parts are ok to get on ebay...but it's always true that you get what you pay for! I think that things like intakes and some exhausts are ok to get, just because it'll provide almost the same result as name brand with maybe 1-2 hp less, but for 1/3 of the cost.. just my 2cents

^^^ I agree thats why I dont get thim cheap @$$ lowering springs or knock off 255 fuel pumps a short throw or a header is quick and easy to fix if it dont work or fit but no one should ever put thare life on the line just to lower thare car 1or2" or be siting on the side of the road becouse the pump went out

Good writeup, Some ebay parts are junk however, there are some things in ebay that are of good quality. Had a friend with an OBX knockoff exhaust system for a 350z and it sounded sweet with no drone or rattle. Again it pays to do your due diligence. Another option is to scour Craigslist ads and buy lightly used parts that are name brand.