It depends on what it is you want out of your car and engine. Swapping in a TT engine is no small task. Do you have an N/A coupe or 2+2? If you have a coupe, I'd just say sell it and buy a tt. Save yourself the effort, pain and misery. If you have a 2+2, I say do the same unless you really, really, really want a tt 2+2. But as far as easier goes, of course it would be easier to build up your N/A engine. Just as long as you realize that you'll never come close to the performance of a tt. For all the money that you'll spend trying to get the N/A up to stock tt specs, you could've spent the same amount on a tt and have triple the hp. It's up to you.

 

getting an N/A to 13 sec is still no small task. It'll require some loot. Try first and foremost, air intake. Then a good flowing exhaust, headers all the way back will make a tremendous difference. Crank pulley would be next. Advance the timing. A lightened flywheel and driveshaft will help acceleration as well. If you can afford the HKS twin ignition amplifier, I say invest. Then the ultimate performance part for the N/A, extrude honed upper and lower plenums. Unless of course you want to replace the bottom end with higher compression pistons and lighter rods. This should take you well into the 13's. Good luck