K&N filter re-located in front of battery with cold air feeds from under car got the following results:
Start Speed 0.0mph
mph s g ft hp
10.0 0.88 0.53 6 35
20.0 1.70 0.56 24 74
30.0 2.49 0.59 53 120
40.0 3.38 0.43 99 121
50.0 4.92 0.35 199 126
60.0 6.31 0.31 312 142
70.0 8.43 0.23 514 134
Pk Power: 69.2mph 8.26s 497ft 151hp
Peak G: 33.2mph 2.72s 64ft 0.61g
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Start Speed 0.0mph
mph s g ft hp
10.0 0.92 0.51 6 34
20.0 1.78 0.53 25 71
30.0 2.60 0.55 55 112
40.0 3.43 0.48 98 131
50.0 4.90 0.34 194 123
60.0 6.20 0.33 299 149
Pk Power: 61.1mph 6.35s 313ft 154hp
Peak G: 36.6mph 3.11s 80ft 0.59g
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I then moved it, and attached it to the elbow coming off the throttle body, and this happened:
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Start Speed 0.0mph
mph s g ft hp
10.0 1.01 0.56 6 36
20.0 1.83 0.55 24 73
30.0 2.67 0.51 55 103
40.0 3.82 0.16 116 50
50.0 5.28 0.31 211 115
60.0 6.77 0.28 332 128
Pk Power: 62.0mph 7.07s 359ft 141hp
Peak G: 12.6mph 1.21s 9ft 0.58g
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Start Speed 0.0mph
mph s g ft hp
10.0 0.98 0.58 6 38
20.0 1.78 0.59 23 78
30.0 2.76 0.48 59 99
40.0 4.05 0.28 127 80
50.0 5.38 0.33 216 121
60.0 6.86 0.28 335 131
Pk Power: 60.4mph 6.92s 341ft 137hp
Peak G: 21.1mph 1.86s 25ft 0.59g
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....oh dear. If you do put one on, make sure you buy some hosing with it and locate it away from the heat of the engine bay. Ive switched to using a Pipercross Viper now, but the relocated K&N worked as well and sounded better.
Although, as Neil says, for pure performance, a panel filter and an RSport ECU are the best bet.