The last few options are a veritable Nissan buffet, like in Las Vegas when you've got the sesame chicken and the mashed potatoes sitting under the same pepperoni pizza roof on your plate. Have you no shame? It's possible to modify the manifold from the rear-wheel-drive Silvia so that it works with the front-wheel-drive drivetrain of the Sentra, but it's a better option to buy a used front-wheel-drive manifold for around $100 and bolt up a Silvia turbo.
The S13 Silvia uses a slightly larger Garrett T25 turbo than the one found under the hood of the Bluebird, which should be good for a few more ponies at higher boost levels. Expect to pay in the neighborhood of $150-$250 for one of these.
Perhaps the S14 Silvia represents the best hot snail donor. It comes with a slightly different, but equally potent version of the T28 used in the Pulsar GTi-R that isn't quite as rare as the turbo used in the little all-wheel-drive hatchback. The price nearly doubles compared to the S13, however. These turbos cost anywhere from $350-$450, depending on where you find them.
The priciest of Nissan's turbos is the ball-bearing T28 found in the Silvia S15, which sports a separated internal wastegate that dumps unused hot air farther along in the piping. This helps avoid unwanted backpressure or sudden spikes in boost, caused by the inherent inability of internally wastegated turbochargers to effectively maintain consistent boost pressure at higher boost levels. The price of admission goes up even further for this unit-$400-$550 in the used market. Alternatively, they can still be purchased brand-new between $800 and $900.
A quick note for those of you thinking about getting creative and using one of the two turbos found on the Skyline GT-R: The ceramic turbine blades have a tendency to snap off at no particular rpm or boost level, putting you back to where you started: a naturally aspirated Sentra. Oh, and they're smaller than the T25 of the Bluebird/Avenir, too.
Regardless of which option you choose, oil plumbing will have to be accounted for. Both a feed and a return, the former routed from the oil sending unit at the back of the block, and the return draining either back into the oil pan or tapped into the block. Because these turbos are water cooled, you'll need to find a water supply and drain as well. The stock coolant lines on the car are right against the firewall. Simply use two T-connectors, and run coolant hose of the proper diameter to the corresponding sides of the turbo.
Because it's unsafe to run more than 8-10 psi on the stock SR20DE, all of the above options typically net wheel-horsepower levels in the high 100s to the low 200s. If you're planning on running more boost, however, it does pay to have one of the more modern Garretts hooked up to the hot side of the engine. The difference between the turbochargers gets exponentially greater as the boost is turned up, being as significant as 50 wheel-hp at 15 psi of boost.
The Sentra SE-R is an excellent way to attack an autocross in box-stock form. But we've never been into the box-stock thing, so why start now? With this many factory options available, it's almost irrational not to turbocharge this powerplant.
Do's and Do Nots
Assuming you've done the above, and slapped a combination of Nissan's ass-hauling solutions onto your SE-R, you should be aware of what you can expect:
* Do not expect the stock transmission to last past much more than 250-wheel hp. It's the unfortunate weak link of the econobox-that-could equation.
* Do expect the SE-R to be good up to about 10 psi on stock internals, but ...
* Do not expect the percolating stock fuel system to suffice under those loads.