Alittle information I picked up and thought I'd pass along. By no means is this an end all be all guide on intercoolers, but this may help some in selecting one that may be suitable for their needs.

From the Garrett Catalog:

The performance estimates were made under the following conditions:
Charge air inlet temp = 250* F
Pressure ratio = approx. 14.7psi
Cooling air temp = 75* F

Tube-Fin design:
Length/ Height/ Width/ Est. HP/ Pressure drop(psi)/ Charge air(*F)/ Effectivness(%)
24" / 15.5" / 2.2" / 450 / 1 psi/ 138*F/ 79%
26" / 18.5" / 2.8" / 600 / .94 psi / 142*F / 81%
26.5" / 12" / 2.8" / 400 / 1 psi / 141*F / 80%
30.3" / 16" / 2.8" / 480 / .9 psi / 150*F / 86%
20" / 11" / 3" / 420 / 1 psi / 119*F / 68%

Bar-Plate design:
Length/ Height/ Width/ Est. HP/ Pressure drop(psi)/ Charge air(*F)/ Effectivness(%)
16" / 10.3" / 2.8" / 320 / .96 psi / 123*F / 70%
16" / 5.4" / 2.8" / 205 / 1 psi / 109*F / 62%
6" / 11.7" / 3" / 175 / .2 psi / 92*F / 53%
8" / 11.7" /3" / 200 / .29 psi / 104*F / 60%
10" / 12" / 3" / 225 / .36 psi / 113*F / 65%
12" / 12" / 3" / 300 / .49 psi / 115*F / 66%
14" / 12" / 3" / 325 / .57 psi / 118*F / 67%
16" / 12" / 3" / 350 / .64 psi / 121*F / 69%
18" / 12" / 3" / 375 / .95 psi / 126*F / 72%
24" / 12" / 3" / 450 / .79 psi / 127*F / 73%
6" / 12" / 3.5" / 150 / .12 psi / 99*F / 57%
8" / 11.7" / 3.5" / 185 / .14 psi / 104*F / 59%
10" / 11.7" / 3.5" / 265 / .32 psi / 105*F / 60%
12" / 12" / 3.5" / 300 / .31 psi / 113*F / 65%
14" / 12" / 3.5" / 350 / .42 psi / 115*F / 65%
16" / 12" / 3.5" / 400 / .52 psi / 112*F / 64%
18" / 12" / 3.5" / 465 / .89 psi / 117*F / 67%
24" / 12" / 3.5" / 500 / 1 psi / 127*F / 72%
24" / 12" / 4" / 520 / .82 psi / 129*F / 74%
16" / 10" / 4" / 400 / .42 psi / 105*F / 60%
6" / 12.4" / 5" / 150 / .1 psi / 90*F / 51%
8" / 11.7" / 4.5" / 165 / .08 psi / 100*F / 57%
10" / 11.7" / 4.5" / 225 / .16 psi / 112*F / 64%
12" / 12" / 4.5" / 275 / .17 psi / 120*F / 69%
14" / 12" / 4.5"/ 300 / .23 psi / 125*F / 72%
16" / 12" / 4.5"/ 345 / .29 psi / 124*F / 71%
18" / 12" / 4.5"/ 420 / .45 psi / 120*F / 69%
24" / 12" / 4.5"/ 480 / .65 psi / 129*F / 74%
27.8" / 12.8" / 5" / 575 / .42 psi / 132*F / 76%
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From the Spearco Catalog:

Core Size(DxWxH) / Horsepower / Flowrate / Core Assembly / Core Only
3.5" / 9.24" / 6" / 630 / 540 / 2-220 / 2-110
3.5" / 6.8" / 11.75" / 215 / 320 / 2-222 / 2-113
3.5" / 5.4" / 32" / 770 / 1100 / 2-290 / 2-114
3.5" / 18.48" / 6" / 760 / 1080 / 2-221 / 2-115
3.5" / 13.6" / 11.75" / 430 / 645 / 2-223 / 2-116
2.25" / 10" / 18.5" / 485 / 695 / 2-228 / 2-118
3.5" / 15.7" / 5.375" / 500 / 720 / 2-227 / 2-119
3.5" / 7.9" / 24" / 520 / 740 / 2-238 / 2-120
3.5" / 7.9" / 12.88" / 470 / 700 / 2-225 / 2-161
3.5" / 15.8" / 12.88" / 700 / 1050 / 2-226 / 2-167
3.5" / 10.4" / 10.5" / 675 / 1010 / 2-245 / 2-172
4.5" / 10.5" / 16.5" / 310 / 460 / 2-257 / 2-173
4.5" / 16.4" / 8.75" / 700 / 1050 / 2-237 / 2-174
4.5" / 25.1" / 6.5" / 615 / 920 / 2-175
4.5" / 26.2" / 11" / 800 / 1200 / 2-233 / 2-176
3.5" / 7.8" / 20" / 510 / 760 / 2-247 / 2-178
4.5" / 19.7" / 20.75" / 670 / 1000 / 2-179
3.5" / 13" / 17.25" / 510 / 760 / 2-235 / 2-180
3.5" / 20.8" / 10.5" / 1000 / 1500 / 2-246 / 2-181
3.5" / 15.6" / 20" / 1000 / 1500 / 2-248 / 2-182
3.5" / 9.5" / 12.4" / 420 / 630 / 2-242 / 2-192
3.5" / 19" / 12.4" / 840 / 1260 / 2-243 / 2-194
3.5" / 9.4" / 8.375" / 335 / 500 / 2-249 / 2-195
3.5" / 18.8" / 8.375" / 670 / 1000 / 2-250 / 2-196
4.5" / 10.93" / 19.5" / 940 / 1400 / 2-234 / 2-197
3.5" / 6.52" / 24" / 430 / 640 / 2-255 / 2-203
3.5" / 13.04" / 24" / 900 / 1280 / 2-255 / 2-205
3" / 14.2" / 18.5" / 675 / 1010 / 2-266 / 2-207
3.5" / 6.5" / 17.25" / 350 / 525 / 2-258 / 2-208
3" / 7.125" / 18.5" / 450 / 670 / 2-262 / 2-209
6" / 5.9" / 11.75" / 450 / 670 / 2-267 / 2-210
6" / 11.8" / 11.75" / 780 / 1180 / 2-268 / 2-211
4.5" / 5.12" / 18.5" / 530 / 790 / 2-263 / 2-212
3.5" / 10.5" / 28" / 530 / 790 / 2-272 / 2-216
3.5" / 21" / 28" / 850 / 1280 / 2-273 / 2-217
4.5" / 5.85" / 16.5" / 530 / 790 / 2-274 / 2-218
2.87" / 10.5" / 15" / 655 / 935 / 2-201 / 2-101
2.87" / 7.8" / 20" / 500 / 710 / 2-247 / 2-178
2.87" / 10.5" / 20"/ 645 / 920 / 2-283 / 2-183
2.87" / 7.8" / 22" / 530 / 760 / 2-239 / 2-105