800-533-6775

Welcome to Tweak'd Performance!


Tweak'd Performance is located in Summerville, SC. Our mission is to provide solutions for people doing popular engine swaps. We specialize in building BRAND NEW plug and play wiring harnesses as well as doing wiring conversions.We intend to supply you with a top-quality product in a timely manner while providing outstanding customer service. If you are looking for digital gauge clusters, EMS systems, gauges, or other performance parts, please visit www.phoenix-tuning.com

Join our mailing list for special offers and updates from Tweak'd Performance!

Name: E-mail:


March 2013:
Tweak'd Performance is proud to sponsor:



You saw us last year at the Import Alliance meet in Charlotte, and you can plan on seeing an even bigger presence at the spring meet in Atlanta, GA. Import Alliance organizes the largest import meets in the country, so if you've been missing it, come out to the Atlanta Motor Speedway on April 21st, and be sure to come say hello at the Tweak'd Performance booth!




March 2013:
NEW from Tweak'd Performance:
Plug and play wiring harnesses for ProEFI and Haltech Engine Management Systems!



Are you running an aftermarket EMS with your new engine swap, such as a Sport 2000 from Haltech or Pro128 from ProEFI? No problem! Forget about dangling connectors from unneeded sensors or cutting and splicing different injector plugs into your harness. No need for one of those bulky patch harnesses either! Get a BRAND NEW harness from Tweak'd Performance that's slim, tidy, tucked away, and doesn't have any unnecessary connectors or wire, and goes STRAIGHT to your new EMS. We have all new ECU connectors and terminals in stock so just let us know which EMS you're using for your project and we'll get you taken care of! Give us a call today at 1-800-533-6775 or email us at sales@tweakdperformance.com!


March 2013:
Expanded Line for Plug and Play Conversions:

2JZ and 1JZ swaps into BMW, Nissan 300ZX, 350Z, Hyundai Genesis, and Scion FR-S!!!


For years Tweak'd Performance has offered Self-Contained 2JZ and 1JZ engine harnesses for more unique cross-platform engine swaps, but this year we're taking it to another level by offering 100% PLUG & PLAY harnesses for some non-Toyota vehicles, including BMW cars, the Nissan 300zx and 350Z, the Hyundai Genesis, and the all-new Scion FR-S! For a quote on a plug and play solution to your engine swap, send us an email or give us a call at 1-800-533-6775!

March 2013:
New Product From Tweak'd Performance:

LS1 Wiring Conversions for Supra, SC300, etc!

Over the past few years, the LS1 engine swap has started becoming more and more popular, and we've gotten enough calls and requests for this wiring conversion that we've decided to add it to our standard services. Plug and play wiring conversions are now available for all LS engines into any Toyota chassis!

Feb 2013:
Did you see us in the latest issue of Super Street Magazine?

Thank you to our customer Ranz Performance and Super Street Magazine for mentioning our work in the March 2013 issue. Check it out!



Jan 2013: Project Jumpstart begins! Special discounts on all wiring harnesses, conversions, and parts from now until Feburary 8th! Contact us today to take advantage of this special deal before we change to 2013 pricing!

Jan 2013:  New Product from Tweak'd Performance: 2JZ-GTE VVTi Engine Harnesses! Also available with braided sleeving and MIL-SPEC firewall connector!






Harness available in our online store

Jan 2013: Also new this month: NEW 7MGTE Engine Harnesses! Replace that crusty old wiring harness on your MK3 Supra Turbo with one of these new, updated replacement harnesses!







Harness available in our online store


Dec 2012: Here at Tweak'd Performance we're happy to release our new MIL-SPEC wiring harnesses. Eliminate your old rubber firewall grommet with these extreme-duty MIL-SPEC bulkhead connectors for the ultimate clean look and the very best harness protection available. Pictures shown alongside our EXTREME DUTY heatshrink looming:







Contact us today at sales@tweakdperformance.com or call 800-533-6775 to see how a MIL-SPEC harness can be used for your application!





Some of our completed projects include:

  • 3SGTE Swap in a '95 Celica
  • 3SGTE (4th gen ST215) swap into a 1994 Celica ST with auto/manual conversion
  • 3SGE BEAMS swap into a 1993 Celica GT
  • Twin-charging a '95 Corolla with a 4AGZE Swap
  • Auto/manual and Rear disc brake conversion, custom 2.5" stainless mandrel-bent exhaust on a 2001 Corolla
  • Auto/manual Conversion on a 1998 Corolla
  • 4AGZE swap into a 1994 Corolla
  • 4AGE Silvertop automatic swap into a 1995 Corolla
  • H22A engine swap into a 1999 Honda Civic
  • KLZE V6 Engine swap into a 1994 Ford Probe
  • 4EFTE swap into a 1994 Paseo
  • Turbo System Installation on a 2005 Nissan 350Z
  • Turbo Upgrade and Dyno Tuning on a 2004 Dodge SRT4
  • 4AGE Silvertop swap into an 1986 MR2


Here are some complete projects in our gallery:

supra swap 1JZGTE Twin Turbo swap into an '87 Supra non-turbo
4agze swap 4AGZE swap into a 1994 Celica ST
3sgte 250whp 3SGTE swap into a 1999 Celica GT, modified, dyno tuned to 250whp
vr4 swap Twin Turbo VR4 engine swap into a 1994 3000GT




We gladly accept:
Visa, Mastercard, American Express, and Discover