This is going to be a continuously updated list. I don't know everything about the 5th gens, so if anyone knows of a mod that I do not have listed on this just shoot me a PM or post up and I'll update the list as it happens.
Performance:
K&N drop in filters
3.5L 33-2031-2 - K&N Replacement Filters, Replacement Air Filter direct from K&N
2.5L 33-2478 - K&N Replacement Filters, Replacement Air Filter direct from K&N
2.5L AEM Intake
K&N Typhoon for 3.5L
69-7063TTK - K&N Intake Kits, Performance Intake Kit
K&N Typhoon for 2.5L
69-7064TS - K&N Intake Kits, Performance Intake Kit
Stillen Exhaust STILLEN Altima Exhaust Systems | STILLEN
Stillen Short Ram Intake: http://www.stillen.com/product/intake-kits/stillen-hi-flow-intake-kit-402875-75283.html
Injen Intake (2.5) : http://www.carid.com/2013-nissan-altima-air-intakes/injen-air-intake-7298327.html
http://injen.com/search.asp?stop=1&Year=2013&MakeID=22&ModelID=14&Eng=2.5L
Stillen Underdrive Pulley:
https://www.stillen.com/stillen-200...120169-400344/vehicle/2014-nissan-altima.html
Goodyear Poly-V Belt for Underdrive Pulley:
https://www.amazon.com/gp/product/B000EI8H8K/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
Racingline Y-Pipe:
Racingline 2013+ Altima Y Pipe +13WHP
Brakes
Stillen Metal Matrix pads http://www.stillen.com/products/brake-pads/high-performance-brake-pads-100388/
Suspension:
Stillen Front Strut Tower Brace:
https://www.stillen.com/stillen-200...110979-307024/vehicle/2014-nissan-altima.html
Stillen Rear Sway Bar:
https://www.stillen.com/suspension/...4320/vehicle/2014-nissan-altima.html?___SID=U
BC Coilovers http://dsautosport.com/shop/bc-racing-br-coilovers-for-2013-nissan-altima/
Eibach Lowering Springs:
Amazon.com: Eibach Springs Inc. 63115-140 Pro-Kit Perf Springs (Set Of 4 Springs): Automotive
RL Strut Tower bar http://racinglineperformance.com/shop/pc/viewPrd.asp?idproduct=95&idcategory=38
Lighting:
BT Trunk Lighting http://racinglineperformance.com/shop/pc/viewPrd.asp?idproduct=93&idcategory=38
BT Footwell Lighting http://racinglineperformance.com/shop/pc/viewPrd.asp?idproduct=94&idcategory=38
Retrofitted Projector Headlights: (PM: tooslow_4_u directly)
HID kits: http://www.theretrofitsource.com/product_info.php?products_id=3955 halo rings are 80mm
Exterior Styling:
CariD mesh grilles: 2013 Nissan Altima Billet Grilles (I'm sure you can also find them on ebay)
Stillen Roof Wing http://www.stillen.com/product/roof-wings/stillen-roof-wing-kb13144-116627.html
Stillen front lip http://www.stillen.com/product/body-components/stillen-front-lip-spoiler-kb13142-115191.html
Bluebat Overlays http://s2.photobucket.com/user/BlueBatmobile2005/library/Nissan%20Altima%205th%20gen%20Overlays?sort=6&page=1
Performance:
K&N drop in filters
3.5L 33-2031-2 - K&N Replacement Filters, Replacement Air Filter direct from K&N
2.5L 33-2478 - K&N Replacement Filters, Replacement Air Filter direct from K&N
2.5L AEM Intake
K&N Typhoon for 3.5L
69-7063TTK - K&N Intake Kits, Performance Intake Kit
K&N Typhoon for 2.5L
69-7064TS - K&N Intake Kits, Performance Intake Kit
Stillen Exhaust STILLEN Altima Exhaust Systems | STILLEN
Stillen Short Ram Intake: http://www.stillen.com/product/intake-kits/stillen-hi-flow-intake-kit-402875-75283.html
Injen Intake (2.5) : http://www.carid.com/2013-nissan-altima-air-intakes/injen-air-intake-7298327.html
http://injen.com/search.asp?stop=1&Year=2013&MakeID=22&ModelID=14&Eng=2.5L
Stillen Underdrive Pulley:
https://www.stillen.com/stillen-200...120169-400344/vehicle/2014-nissan-altima.html
Goodyear Poly-V Belt for Underdrive Pulley:
https://www.amazon.com/gp/product/B000EI8H8K/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
Racingline Y-Pipe:
Racingline 2013+ Altima Y Pipe +13WHP
Brakes
Stillen Metal Matrix pads http://www.stillen.com/products/brake-pads/high-performance-brake-pads-100388/
Suspension:
Stillen Front Strut Tower Brace:
https://www.stillen.com/stillen-200...110979-307024/vehicle/2014-nissan-altima.html
Stillen Rear Sway Bar:
https://www.stillen.com/suspension/...4320/vehicle/2014-nissan-altima.html?___SID=U
BC Coilovers http://dsautosport.com/shop/bc-racing-br-coilovers-for-2013-nissan-altima/
Eibach Lowering Springs:
Amazon.com: Eibach Springs Inc. 63115-140 Pro-Kit Perf Springs (Set Of 4 Springs): Automotive
RL Strut Tower bar http://racinglineperformance.com/shop/pc/viewPrd.asp?idproduct=95&idcategory=38
Lighting:
BT Trunk Lighting http://racinglineperformance.com/shop/pc/viewPrd.asp?idproduct=93&idcategory=38
BT Footwell Lighting http://racinglineperformance.com/shop/pc/viewPrd.asp?idproduct=94&idcategory=38
Retrofitted Projector Headlights: (PM: tooslow_4_u directly)
HID kits: http://www.theretrofitsource.com/product_info.php?products_id=3955 halo rings are 80mm
Exterior Styling:
CariD mesh grilles: 2013 Nissan Altima Billet Grilles (I'm sure you can also find them on ebay)
Stillen Roof Wing http://www.stillen.com/product/roof-wings/stillen-roof-wing-kb13144-116627.html
Stillen front lip http://www.stillen.com/product/body-components/stillen-front-lip-spoiler-kb13142-115191.html
Bluebat Overlays http://s2.photobucket.com/user/BlueBatmobile2005/library/Nissan%20Altima%205th%20gen%20Overlays?sort=6&page=1