You're gonna want to use aux. fuel with any of the Garrett options as they offer more on top at the cost of a slower spool. If you're willing to cross that $1200 hurtle, the GTX2860R Gen 2 offers newer and more efficient internals and geometry than the older turbos, including the GT2554R and the MRX on which it's based. Then there's the whole question of using a v-flange adaptor vs. spending another $800 to get a tubular v-flange manifold. There's also talk of needing a new downpipe and, maybe, exhaust to let the Garrett solutions breath. I'd wager that the GTX2860R Gen 2 does almost everything down low that the smaller and older turbos do and offers way more up high so, if you're willing to spend the money for the turbo and the supporting mods., I think that the GTX2860R Gen 2 is the best big turbo by a big margin.
But, since we're talking bang for the buck, aux. fuel is off the table so it's gotta be a hybrid. If I were buying new I'd go with Whoosh; Ron's customer service is next to none and he's got a customer beating the snot out of his hybrid and breaking records. If used is an option then an X-37/47. Cyborgs with the right seals installed are supposed to be a good option but I can't shake the bad taste left by the Cyborg/DHM collapse and the resulting complete lack of support. The S280 *might* offer hybrid-ish spool without the reliability problems of the X-47R, *might* flow well up high, is designed to use the stock flange, is designed by a well-respected vendor, and is priced well, but there's not enough info. in the wild for me to pull the trigger.
I had settled on waiting for more information re. the S280 and, then decide between it and the GTX2860R Gen 2 but, then, a X-47R for a great price came up. I'm going to tune all the way through Ron's Extrude Hone-ed exhaust manifold and aux. fuel with the X-47R (fingers crossed that it'll stay together) and then take a look at the S280 vs. GTX question, again. I'm building my FiST for autocross *and* time-attack so I'm thinking that the S280 is going to offer the best combination of throttle response and higher-rev. performance.
![[bootyshake]](/images/smilies/icon_smile_bootyshake.gif "Booty Shake [bootyshake]"){kind=icon}
